Dissertations / Theses on the topic 'Chloroplast expression'
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Sornarajah, Renuka. "Chloroplast control of nuclear gene expression." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364277.
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Chandler, Aglaia. "The role of RpoT;3 in chloroplast development and gene expression." Thesis, [College Station, Tex. : Texas A&M University, 2005. http://hdl.handle.net/1969.1/ETD-TAMU-1701.
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Kindgren, Peter. "The chloroplast talks : Insights into the language of the chloroplast in Arabidopsis." Doctoral thesis, Umeå universitet, Institutionen för fysiologisk botanik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-36166.
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The chloroplast originates from an endosymbiotic event 1.5 billion years ago, when a free living photosynthetic bacteria was engulfed by a eukaryotic host. The chloroplastic genome has through evolution lost many genes to the nuclear genome of the host. To coordinate the gene expression between the two genomes, plants have evolved two types of communication, nucleus-to-plastid (anterograde) and plastid-to-nucleus (retrograde) signalling. This thesis will focus on retrograde communication with emphasis on redox and tetrapyrrole mediated signalling. In this thesis, we establish the tetrapyrrole Mg-ProtoIX as an important retrograde negative regulator of nuclear encoded plastid proteins. We show that Mg-ProtoIX accumulates in both artificial and natural stress conditions, and that the accumulation is tightly correlated to regulation of nuclear gene expression. Using confocal microscopy, we could visualize Mg-ProtoIX in the cytosol during stress conditions. In addition, exogenously applied Mg-ProtoIX stayed in the cytosol and was enough to trigger a signal to the nucleus. The results presented here indicate that Mg-ProtoIX is transported out of the chloroplast to control nuclear gene expression. Mg-ProtoIX mediated repression of the nuclear gene, COR15a, occurs via the transcription factor HY5. HY5 is influenced by both plastid signals and the photoreceptors. Here, we show that photoreceptors are part of Mg-ProtoIX mediated signalling as well as excess light adaptation. We identified the blue light receptor, CRY1, as a light intensity sensor that partly utilizes HY5 in the high light response. To further understand the high light regulation of nuclear genes, we isolated a mutant with redox insensitive (rin) high light response. The rin2 mutant has a mutated plastid protein with unknown function. Characterization of the rin2 mutant revealed that the protein is important in regulating plastid gene expression as well as nuclear gene expression. The rin2 mutant is the first characterized rin mutant and could prove important in elucidating the cross-talk between redox mediated coordination between the plastid and the nuclear genome.
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Kremnev, Dmitry. "Get in tune : chloroplast and nucleus harmony." Doctoral thesis, Umeå universitet, Institutionen för fysiologisk botanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-96171.
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Photosynthetic eukaryots emerged as a result of several billion years of evolution between proeukaryotic cell and ancestral cyanobacteria that formed modern chloroplasts. The symbiotic relationship led to significant rearrangements in the genomes of the plastid and the nucleus: as many as 90 % of all the plastid genes were transferred to the nucleus. The gene transfer has been accompanied by the development of sophisticated regulatory signaling networks originating in the organelle (retrograde) and in the nucleus (anterograde) that coordinate development of the plastid and ensure adequate cell responses to stress signals. In this thesis I have demonstrated that transcriptional activity of PEP in the chloroplast is essential for proper embryo and seedling development in Arabidopsis thaliana. The function of PEP is dependent on the nuclear encoded PEPassociated factor PRIN2 that is able to sense the redox status of the plastid during seedling development and different stress. In response to the plastid status PRIN2 modulates the transcription activity of the PEP enzyme complex. We further established that PRIN2, as an essential component for full PEP activity, is also required to emit the Plastid Gene Expression (PGE) retrograde signal to regulate the Photosynthesis-Associated Nuclear Genes (PhANG) in the nucleus during early seedling growth via GUN1. On the other hand, regulation of PhANG expression during the High Light (HL) conditions requires functional PRIN2 and PEP activity but is GUN1-independent. Another retrograde signal produced by the developing chloroplast is associated with the tetrapyrrole biosynthesis pathway. We have established that accumulation of the chlorophyll intermediate MgProtoIX-ME in the crd mutant triggers repression of the PhANG expression, and this negative signal is mediated by a cytoplasmic protein complex containing the PAPP5 phosphatase. The nuclear targets that receive the tetrapyrrole mediated signal are GLK1 and GLK2 transcription factors that control the PhANG expression and the expression of the enzymes involved in the biosynthesis of chlorophyll.Fotosyntetiserande eukaryoter uppstod från en endosymbiotisk interaktion under några miljarder år mellan en ur-eukaryot och kloroplastens förfader, den prokaryota cyanobakterien. Den symbiotiska händelsen ledde till att kloroplastens och kärnans genom blev väsentligt förändrade. Så småningom överförde kloroplasten så många som 90 % av dess gener till cellkärnan. För att koordinera genutrycket från de två genomen utvecklade växtcellen ett sofistikerat signalsystemen som inkluderar: plastid-kärn (retrograd) och kärn-plastid (anterograd) signalering som styr kloroplastens utveckling och förmåga att anpassa sig till stressförhållanden. Den här avhandlingen beskriver kloroplastens maskineri för genuttryck (PEP) som en nödvändig komponent för embryo- och växtutvecklingen hos Arabidopsis thaliana. PEP funktionen är beroende av det kärnkodade kloroplastproteinet PRIN2 som är associerat med PEP. PRIN2 mottar redox signaler från plastiden och förändrar genuttrycksaktivitet under kloroplastens utvecklingen eller under olika stressförhållanden. Jag visar dessutom att PRIN2 spelar en viktig roll i överföring av kloroplastens signal som kommunicerar genuttrycksaktivitet (PGE) via GUN1 till kärnan där den styr uttryck av de kärnkodade fotosyntetesgenerna (PhANG). Under högljus stressförhållanden styrs dock PhANG-uttrycket av signaler som uppstår från PEP-aktivitet och PRIN2 men som är oberoende av GUN1. Vidare finns det en annan retrograd signal som har sitt ursprung i biosyntesen av tetrapyrroler. Jag har visat att ackumuleringen av tetrapyrrolen MgProtoIX-ME i crd-mutanten framkallar nedreglering av PhANG-uttryck genom interaktion med ett fosfatas (PAPP5) i cytosolen. GLK1 and GLK2 är två transkriptionsfaktorer som tar emot den tetrapyrrole-medierade signalen i sin tur styr biosyntes av chlorofyll och PhANG uttryck.
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Ruhlman, Tracey. "Determinants of Chloroplast Gene Expression and Applications of Chloroplast Transformation in Lactuca Sativa and Nicotiana Tabacum." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2854.
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Genetic modification of plastids in the model plant tobacco (Nicotiana tabacum) has demonstrated that numerous foreign gene products can accumulate to high levels in this setting. Plastid biotechnology is maturing to encompass the improvement of food and feed species and the production of biopharmaceutical proteins for oral delivery necessitating development of stable transplastomic edible plants. In the interest of establishing an edible platform we have investigated the use of native and foreign regulatory elements in relation to foreign gene expression in plastids. Multiple sequence alignments of intergenic regions for 20 species of angiosperm showed that despite 95% identity in the coding region, identity in the psbA upstream region is 59% across all taxa examined, other gene coding regions displayed sequence identity of 80-97%, whereas the non-coding regions were 45-79% suggesting that our physical data can be extrapolated beyond the model presented. We found that by exchanging psbA untranslated regions (UTRs) between N. tabacum and lettuce (Lactuca sativa), the expression of the CTB-proinsulin (CTB-Pins) monocistronic transcript declined by 84% and foreign protein accumulation was reduced by as much as 97% in mature leaves. Polyribosome association assays suggest that ribosome-free transgenic transcripts are stabilized where the native UTR is employed. RNA EMSA revealed that binding proteins interacted with psbA 5' UTRs in a species specific manner and the half life of the L. sativa 5'UTR-CTB-Pins mRNA was reduced by 3.7 fold in N. tabacum stromal extracts. Our data indicate that the use of species-specific regulatory elements could lead to establishment of reproducible plastid transformation in desirable target species such as L. sativa. Using transplastomic L. sativa for oral delivery of bioencapsulated CTB-Pins we delayed the onset of diabetes in NOD mice when retinyl acetate supplement was provided compared to untouched mice. In this 30 week study we monitored blood glucose levels and evaluated the in vitro suppressive capacity of regulatory T cells isolated from diabetic mice. Whether delay or prevention was achieved appeared to be a function of antigen dose as high dose resulted in a nine week delay of onset while low dose reduced the incidence of diabetes by 36%. In addition we have evaluated metabolic engineering in the N. tabacum model where we generated cis-genic lines expressing nucleus-encoded methionine pathway enzymes in plastids. Transplastomic expression of Cystathionine gamma-Synthase led to a three-fold increase in enzyme activity and a doubling of methionine content in leaves without a deleterious phenotype. In exploring molecular mechanisms supporting gene expression in plastids and applying transplastomic technology to real human problems this work seeks address the potential of plastid biotechnology for improvement of commodity crops and production of biopharmaceuticals.Ph.D.
Department of Biomolecular Science
Other
Biomedical Sciences PhD
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Zainuddin, Zarina. "Expression of vitamin B₁₂ enzymes in Chlamydomonas reinhardtii chloroplast." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609492.
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Barthet, Michelle Marie. "Expression and Function of the Chloroplast-encoded Gene matK." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/26287.
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The chloroplast matK gene has been identified as a rapidly evolving gene at nucleotide and corresponding amino acid levels. The high number of nucleotide substitutions and length mutations in matK has provided a strong phylogenetic signal for resolving plant phylogenies at various taxonomic levels. However, these same features have raised questions as to whether matK produces a functional protein product. matK is the only proposed chloroplast-encoded group II intron maturase. There are 15 genes in the chloroplast that would require a maturase for RNA splicing. Six of these genes have introns that are not excised by a nuclear imported maturase, leaving MatK as the only candidate for processing introns in these genes. Very little research has been conducted concerning the expression and function of this important gene and its protein product. It has become crucial to understand matK expression in light of its significance in RNA processing and plant systematics. In this study, we examined the expression, function and evolution of MatK using a combination of molecular and genetic methods. Our findings indicate that matK RNA and protein is expressed in a variety of plant species, and expression of MatK protein is regulated by development. In addition, matK RNA levels are affected by light. Furthermore, genetic analysis has revealed that although MatK has a high rate of amino acid substitution, these substitutions are not random but are constrained to maintain overall chemical structure and stability in this protein. We have also identified an alternate start codon for matK in some plant species that buffers indels (insertions and deletions) in the open reading frame (ORF) that are not in multiples of three in the gene sequence. Usually, indels not in multiples of three result in frame shifts that destroy the reading frame. Our results indicate that an out-of-frame matK start codon in some orchids compensates for these otherwise deleterious indels. This research represents the first in-depth analysis of matK gene expression and contributes to several fields of biology including plant systematics, genetics and gene expression.Ph. D.
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Kawazoe, Ryo. "Control of chloroplast gene expression by a circadian clock in Chlamydomonas reinhardtii /." Digital version:, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p9992832.
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Bateman, Joseph Matthew. "The maintenance and expression of foreign genes in the chloroplast of Chlamydomonas." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391710.
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Hong, Ling. "Gene structure and expression of the Euglena gracilis chloroplast psbB and petB operons." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186930.
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Euglena gracilis has been used as a model for studying the chloroplast genome and gene expression during chloroplast biogenesis. My graduate research has been focused on the following two areas: (1) DNA sequencing of part of the Euglena gracilis chloroplast genome, (2) Euglena chloroplast RNA metabolism, such as intercistronic RNA processing and intron splicing. The region that I characterized is between the psbB and rbcL loci on the Euglena gracilis chloroplast genome. Three photosystem II genes (psbT, psbN and psbH), one cytochrome b6 gene (petB) and two ATPase subunit genes (atpB and atpE) have been identified. Based on northern hybridization analysis, the Euglena gracilis chloroplast petB, atpB and atpE genes are cotranscribed as a tricistronic operon. Through cDNA analysis of petB-atpB-atpE pre-mRNA, eight introns have been identified. Two independent intercistronic RNA processing events and 11 splicing reactions lead to the accumulation of the mature petB, atpB and atpE monocistronic mRNAs. The mRNAs from psbB, psbT, psbH and psbN genes have been analyzed by northern hybridization, S1 nuclease protection and primer extension RNA sequencing. psbB and psbT are cotranscribed, while psbH and psbN are cotranscribed on the opposite strand. The 5' end of the psbN-psbH transcript and the intercistronic cleavage sites between psbB-psbT and psbN-psbH were determined. Through a combination of cDNA cloning and sequencing, northern hybridization and S1 nuclease protection analysis of the partially spliced psbT pre-mRNAs, the 1352 nt psbT intron has been characterized as a complex twintron with overlapping internal introns and alternative splicing pathways. In the predominant pathway, two internal group II introns are not orderly spliced. In an alternative pathway, splicing of a group III intron occurs. This group III intron is recruited from sequences of two group II introns. The generation of this group III intron is the first evidence that a group III intron can be derived from portions of existing group II introns. The mechanism of group III intron formation may also be relevant to the evolution of nuclear introns from putative group II intron ancestors.
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Tah, Tapashree Schoelz James E. "Chloroplast GFP expression in tobacco plants agroinfiltrated with tobacco mosaic virus based vectors." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6604.
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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 19, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. James E. Schoelz. Includes bibliographical references.
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Lenzoni, Gioia. "Calcium signalling in the chloroplast and in the regulation of nuclear gene expression." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12348/.
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Calcium is a universal second messenger involved in nearly every aspect of plant physiology and development. In response to a variety of biotic or abiotic stresses, calcium rapidly and transiently increases in the cytosol and in this way triggers the appropriate downstream response. To date, most of the research on calcium has focused on cytosolic calcium signalling, however recent advances have demonstrated that in the chloroplast Ca2+ concentrations are also controlled, and that chloroplast calcium signalling is involved in regulating the plant cell physiology. This thesis describes work investigating both cytosolic and chloroplast calcium signalling, In the first case, I examined how cytosolic Ca2+ increases with different kinetics (Ca2+-signatures) can encode specific information, and how this can be translated into appropriate changes in transcript expression. To this aim, a dynamic mathematical model of the SA-mediated pathogen network was developed. Calcium is responsible for activating this defence pathway by a complex regulation of the components of this network. This model was able to predict fold-changes and kinetics of gene expression in response to any given calcium signature, hence it was able to accurately describe how specificity is encoded in plant cells. The properties emerging from this model provided insights into the mechanistic basis of calcium signature decoding. Work on chloroplast calcium signalling focused on two different aspects. Firstly, the hypothesis that chloroplast calcium might regulate chloroplast gene expression was tested, and it was found to not be the case. Secondly, a new chloroplast-specific calcium response was discovered, in response to heat. Properties of this response were investigated, as well as its possible physiological functions. Finally, by using this calcium response as a readout, I addressed the question of heat-sensing in plants. Using this approach I discovered that there is a prominent role for membrane fluidity in controlling this heat-induced calcium increase.
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Prikryl, Jana 1976. "Functions of organelle-specific nucleic acid binding protein families in chloroplast gene expression." Thesis, University of Oregon, 2009. http://hdl.handle.net/1794/10614.
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xii, 83 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.My dissertation research has centered on understanding how nuclear encoded proteins affect chloroplast gene expression in higher plants. I investigated the functions of three proteins that belong to families whose members function solely or primarily in mitochondrial and chloroplast gene expression; the Whirly family (ZmWHY1) and the pentatricopeptide repeat (PPR) family (ZmPPR5 and ZmPPR10). The Whirly family is a plant specific protein family whose members have been described as nuclear DNA-binding proteins involved in transcription and telomere maintenance. I have shown that ZmWHY1 is localized to the chloroplast where it binds nonspecifically to DNA and also binds specifically to the atpF group II intron RNA. Why1 mutants show reduced atpF intron splicing suggesting that WHY1 is directly involved in atpF RNA maturation. Why1 mutants also have aberrant 23S rRNA metabolism resulting in a lack of plastid ribosomes. The PPR protein family is found in all eukaryotes but is greatly expanded in land plants. Most PPR proteins are predicted to localize to the mitochondria or chloroplasts where they are involved in many RNA-related processes including splicing, cleavage, editing, stabilization and translational control. Our results with PPR5 and PPR10 suggest that most of these activities may result directly from the unusually long RNA binding surface predicted for PPR proteins, which we have shown imparts two biochemical properties: site-specific protection of RNA from other proteins and site-specific RNA unfolding activity. I narrowed down the binding site for PPR5 and PPR10 to ∼45 nt and 19 nt, respectively. I showed that PPR5 contributes to the splicing of its group II intron ligand by restructuring sequences that are important for splicing. I used in vitro assays with purified PPR10 to confirm that PPR10 can block exonucleolytic RNA decay from both the 5' and 3' directions, as predicted by prior in vivo data. I also present evidence that PPR10 promotes translation by restructuring its RNA ligand to allow access to the ribosome. These findings illustrate how the unusually long RNA interaction surface predicted for PPR proteins can have diverse effects on RNA metabolism. This dissertation includes both previously published and unpublished co-authored material.
Committee in charge: Eric Selker, Chairperson, Biology; Alice Barkan, Advisor, Biology; Victoria Herman, Member, Biology; Karen Guillemin, Member, Biology; J. Andrew Berglund, Outside Member, Chemistry
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Kohchi, Takayuki. "GENE ORGANIZATION AND EXPRESSION OF THE CHLOROPLAST DNA FROM A LIVERWORT,MARCHANTIA POLYMORPHA." Kyoto University, 1989. http://hdl.handle.net/2433/78201.
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Hickey, Ashley N. "Expression of CTB-proinsulin in transgenic chloroplasts." Honors in the Major Thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1088.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Burnett College of Biomedical Sciences
Molecular and Microbiology
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Herrera, Rodriguez Leopoldo. "Genetic engineering tools for transforming the nucleus and chloroplast of microalgae." Thesis, University of Manchester, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727988.
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Biotechnology of microalgae is a fast-growing field and several species have become targets for transgenic manipulation. Microalgae provide low-cost and scalable production platforms for manufacturing recombinant proteins and other high value products. However, the exploitation of microalgae as expression systems is restricted by the low yield of recombinant proteins and the limited availability of tools for the genetic manipulation of commercially important species. This thesis explores transgene instability and gene autoregulation as causes for low recombinant protein accumulation in the chloroplast of Chlamydomonas reinhardtii and describes the isolation of a mutant phytoene desaturase (PDS) gene which confers resistance to the herbicide norflurazon for future use as a selection marker for the marine microalga Dunaliella tertiolecta. Recombination between short dispersed DNA repeats (SDR) found in the chloroplast genome of C. reinhardtii was identified as a cause of transgene instability. The genes coding for β-glucuronidase (GUS) and peridinin-chlorophyll binding protein (PCP) were inserted in the chloroplast genome next to the atpB 3' UTR by homologous recombination. Recombination of a 30bp SDR located within the 3' UTR of atpB was identified as the cause of transgene excision in the transplastomic lines. Such transgene instability was tackled by replacing the 3' UTR of atpB with the rbcL 3' UTR from D. tertiolecta. Using this 3'UTR sequence from a different species produced a photosynthetic strain and prevented excision of the transgene by SDR recombination in all transfomants. Very low levels of recombinant GUS and PCP accumulated in chloroplast transformants when using the psbD 5' regulatory region to drive their expression. To address low levels of accumulation caused by regulatory pathways that inhibit transgene expression, I have engineered the chloroplast genome of a non-photosynthetic atpB mutant of C. reinhardtii by replacing the endogenous psbD promoter and 5'UTR with the promoter and 5'UTR of psbA. The engineered strain was subsequently transformed with the wildtype atpB and two different reporter genes driven by the psbD regulatory regions: gusA and kat, which code for GUS and the fluorescent protein Katushka respectively. Analysis of the transformants showed that accumulation of recombinant proteins in our engineered strain was 10 to 20 fold higher than in the nonengineered cells. Most of the selectable markers used in plants and algae are inefficient in Dunaliella, which is naturally resistant to many of the antibiotics used for the selection of transformants. Norflurazon inhibits PDS, an essential enzyme for carotenoid biosynthesis. Using forward genetics I have isolated, sequenced and characterised mutant PDS alleles conferring norflurazon resistance in D. tertiolecta. Independent mutations in pds, leading to substitutions R265C, S472L, S472F and L502F, all result in high resistance to norflurazon but differ in sensitivity to other bleaching herbicides. By mapping the four amino acid substitutions on 3D models of D. tertiolecta PDS I determined that R265C, S472L, S472F and L502F, cluster together in proximity to a Rossman-like domain and to aminoacids F128 and V469, previously reported to confer norflurazon resistance. This suggests that the mode of action of norflurazon is by competition with flavin adenine dinucleotide (FAD) for its binding site. A unique aspect of the R265C substitution is its negative cross-resistance to diflufenican and beflutamid which could be advantageous for its use as a positive/negative selection marker for transformation.
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Lezhneva, Lina. "Identification of novel nuclear factors required for chloroplast gene expression and photosystem I assembly." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-40353.
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Robson, Julia. "The construction of an expression vector for the transformation of the grape chloroplast genome." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53621.
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Thesis (MSc)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: The genetic information of plants is found in the nucleus, the mitochondria, and the plastids. The DNA of plastids is comprised of multiple copies of a double-stranded, circular, prokaryoticallyderived genome of -150 kb. The genome equivalents of plastid organelles in higher plant cells are an attractive target for genetic engineering as high protein expression levels are readily obtained due to the high genome copy number per organelle. The resultant proteins are contained within the plastid organelle and the corresponding transgenes are inherited, in most crop plants, uniparentally, preventing pollen transmission of DNA. Plastid transformation involves the uniform modification of all the plastid genome copies, a process facilitated by homologous recombination and the non-Mendelian segregation of plastids upon cell division. The plastid genomes are in a continuous state of inter- and intra-molecular exchange due to their common genetic complement. This enables the site-specific integration of any piece of DNA flanked by plastid targeting sequences, via homologous recombination. The attainment of homoplasmy, where all genomes are transformed, requires the inclusion of a plastid-specific selectable marker. Selective pressure favouring the propagation of the transformed genome copies, as well as the random segregation of plastids upon cell division, make it feasible to acquire uniformity and hence genetic stability. From this, a complete transplastomie line is obtained where all plastid genome copies present are transgenic, having eliminated all wild-type genome copies. The prokaryotic nature of the chloroplast genetic system enables expression of multiple proteins from polycistronic mRNAs, allowing the introduction of entire operons in a single transformation. Expression cassettes in vectors thus include single regulatory elements of plastid origin, and harbour genes encoding selectable and screenable markers, as well as one or more genes of interest. Each coding region is preceded by an appropriate translation control region to ensure efficient translation from the polycistronic mRNA. The function of a plastid transformation vector is to enable transfer and stable integration of foreign genes into the chloroplast genomes of higher plants. The expression vector constructed in this research is specific for the transformation of the grape chloroplast genome. Vitis vinifera L., from the family, Vitaceae, is the choice species for the production of wine and therefore our target for plastid transformation. All chloroplast derived regulatory elements and sequences included in the vector thus originated from this species.
AFRIKAANSE OPSOMMING: Die genetiese inligting van plante word gevind in die kern, die mitochondria, en die plastiede. Die DNA van plastiede bestaan uit veelvuldige kopieë van 'n ~ 150 kb dubbelstring, sirkulêre genoom van prokariotiese oorsprong. Die genoomekwivalente van plastiede in hoër plante is 'n aantreklike teiken vir genetiese manipulering, aangesien die hoë genoom kopiegetal per organel dit moontlik maak om gereeld hoë vlakke van proteïenuitdrukking te verkry. Hierdie proteïene word tot die plastied beperk, en die ooreenstemmende transgene word in die meeste plante sitoplasmies oorgeërf, sonder die oordrag van DNA deur die stuifmeel. Plastied transformasie behels die uniforme modifikasie van al die plastied genoomkopieë, 'n proses wat deur homoloë rekombinasie en die nie-Mendeliese segregasie van plastiede tydens seldeling gefasiliteer word. As gevolg van die gemeenskaplike genetiese komplement, vind aanhoudende interen intra-molekulêre uitruiling van plastiedgenome plaas. Dit maak die setel-spesifieke integrasie, via homoloë rekombinasie, van enige stuk DNA wat deur plastied teikenvolgordes begrens word, moontlik. Vir die verkrying van homoplasmie, waar alle genome getransformeer is, word die insluiting van 'n plastiedspesifieke selekteerbare merker benodig. Seleksiedruk wat die vermeerdering van die getransformeerde genoomkopieë bevoordeel, en die lukrake segregasie van plastiede tydens seldeling, maak dit moontlik om genetiese stabiliteit en uniformiteit van die genoom te verkry. Dit kan op sy beurt tot die verkryging van 'n volledige transplastomiese lyn lei, waar alle aanwesige plastiedgenome transgenies is, en wilde tipe genoomkopieë geëlimineer is. Die prokariotiese aard van die chloroplas genetiese sisteem maak die uitdrukking van veelvuldige proteïene vanaf polisistroniese mRNAs moontlik, wat die toevoeging van volledige operons in 'n enkele transformasie toelaat. Uitdrukkingskassette in vektore bevat dus enkel regulatoriese elemente van plastied oorsprong, gene wat kodeer vir selekteerbare en sifbare merkers, asook een of meer gene van belang (teikengene). Voor elke koderingsstreek, is daar ook 'n toepaslike translasie beheerstreek om doeltreffende translasie vanaf die polisistroniese mRNA te verseker. Die funksie van 'n plastied transformasie vektor is om die oordrag en stabiele integrasie van transgene in chloroplasgenome van hoër plante moontlik te maak. Die uitdrukkingsvektor wat in hierdie studie gekonstrueer is, is spesifiek vir die transformasie van die druif chloroplasgenoom. Vitis vinifera L., van die familie Vitaceae, is die voorkeur species vir die produksie van wyn, en daarom die teiken vir plastied transformasie. Alle chloroplast-afgeleide regulatoriese elemente en volgordes wat in hierdie vektor ingesluit is, het huloorsprong vanaf VUis vinifera L.
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Tangphatsornruang, Sithichoke. "Chloroplast transformation : studies on plastid gene expression and production of viral antigens in tobacco." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615922.
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Allorent, Guillaume. "Expression du génome plastidial d'Arabidopsis thaliana pendant la formation des graines." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00680102.
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L'expression du génome plastidial, un des trois génomes (nucléaire, mitochondrial et plastidial) qui coexistent dans les cellules végétales, est assurée par trois ARN polymérases. Deux NEP (Nuclear-Encoded RNA Polymerase) transcrivent la plupart des gènes de ménage tandis que la PEP (Plastid-Encoded RNA Polymerase) transcrit principalement les gènes liés à la fonction photosynthétique en s'associant à des facteurs de transcription d'origine nucléaire (facteurs sigma) importés dans le plaste. De précédents travaux dans l'équipe ont montré que, contrairement aux observations généralement admises, les trois ARN polymérases sont nécessaires pour assurer une germination efficace des graines d'Arabidopsis. L'objectif de notre travail est de comprendre comment ces enzymes ont été mises en place au cours de la formation de la graine. Pour cela, nous avons analysé l'expression de l'appareil transcriptionnel et du transcriptome plastidial durant les trois phases de formation de la graine d'Arabidopsis thaliana, c'est à dire l'embryogenèse, la maturation (phase photosynthétique) et la dessiccation. L'expression globale du transcriptome plastidial montre que les changements quantitatifs des transcrits sont les plus élevés pour les transcrits des gènes liés à la fonction photosynthétique. Ils sont très fortement exprimés pendant la phase de la maturation et diminuent ensuite, comme leurs protéines correspondantes. Nous observons également une forte accumulation des protéines codant les NEP et les sous unités de la PEP pendant la période de maturation des graines, suivie d'une forte diminution pendant la dessiccation. Cependant, les ARNm correspondants augmentent pendant la dessiccation. Le stockage de ces ARNm codant l'appareil transcriptionnel constitue une étape cruciale pour l'efficacité de la germination de la graine. La quantité de matériel biologique disponible pour ces études étant très limitée, nous avons développé une nouvelle technique de détection des ADNc sur lame de quartz, utilisant la microscopie TIRF. Cette méthode augmente la résolution (elle permet la détection de molécules uniques) et diminue considérablement la quantité de matériel nécessaire à l'hybridation. Finalement, nous avons analysé les conditions sous lesquelles se déroule la photosynthèse embryonnaire. Ces études ont montré que la photosynthèse dans l'embryon se déroule dans un environnement particulier, hypoxique, et sous un éclairement enrichi en longueurs d'onde vertes. Cependant, la structure et le fonctionnement de l'appareil photosynthétique sont semblables à ceux d'une feuille. Nous avons également montré que l'étape transitoire de la photosynthèse embryonnaire est indispensable à la vigueur germinative des graines. Les résultats obtenus lors de ce travail apportent de nouvelles informations sur le fonctionnement de la transcription plastidiale au cours de la formation de la graine. L'importance de l'accumulation d'ARNm, de certaines protéines ainsi que celle de la photosynthèse embryonnaire dans la vigueur germinative ont été soulignées. Ces données permettent de comprendre comment l'efficacité de la germination est conditionnée par la phase de formation de la graine.
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Radebaugh, Catherine Ann 1956. "Characterization of the structure and expression of the Euglena gracilis chloroplast rpoC1 and rpoC2 gene loci." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185057.
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In order to expand our understanding of the expression of chloroplast genes, the structure and expression of the Euglena gracilis rpoC1 and rpoC2 loci were studied. The rpoC1 and rpoC2 gene products are similar to the amino- and carboxyl-terminal regions of the $\beta\sp\prime$ subunit of E. coli RNA polymerase. The nucleotide sequence (7,270 bp) was determined for 100% of both strands encoding these two genes. The rpoC1 and rpoC2 genes are located downstream and in the same polarity as the rpoB gene. The organization of the Euglena rpoB-rpoC1-rpoC2 genes is conserved in plant chloroplasts and is similar to the E. coli rpoB-rpoC operon. The Euglena rpoC1 gene (586 codons) encodes a polypeptide with a predicted molecular weight of 68,043. The rpoC1 gene is interrupted by one group II intron of 349 bp, seven group III introns of 107, 100, 119, 97, 110, 102 and 103 bp, and three atypical introns of 210, 213 and 198 bp. The Euglena rpoC2 gene (830 codons) encodes a polypeptide with a predicted molecular weight of 94,628. The rpoC2 gene is interrupted by two group II introns of 580 and 514 bp, respectively. All of the exon-exon junctions were experimentally determined via cDNA cloning and sequencing analysis. Multiple protein alignments of the rpoC1 and rpoC2 gene products with related proteins from bacteria and chloroplasts were used to identify conserved regions. Transcripts from the rpoC1 and rpoC2 loci were characterized via Northern analysis. The rpoB, rpoC1 and rpoC2 genes are cotranscribed. Fully spliced tri-, di- and monocistronic transcripts were detected with hybridization probes specific for each gene. The relative abundance of the rpoC1 and rpoC2 transcripts is similar in RNA from dark- and light-grown Euglena. The mature 5'-ends of the rpoC1 and rpoC2 genes were mapped by primer extension. The 3'-end of the mature rpoC2 transcript was localized via an S1 nuclease protection assay. The rpoC1 and rpoC2 gene products were also compared to the largest subunits of RNA polymerases from archaebacteria and eukaryotes. The evolution of the Euglena genes is discussed.
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Juszczak, Ilona [Verfasser]. "Natural genetic variation in the expression regulation of chloroplast antioxidant system among A. thaliana accessions. / Ilona Juszczak." Berlin : Freie Universität Berlin, 2013. http://d-nb.info/1042441324/34.
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Yepiz, Plascencia Gloria Martina. "Characterization of the structure and expression of the Euglena gracilis chloroplast rpoB and 23S ribosomal-RNA genes." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/282094.
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The rpoB gene coding for a β-like subunit (homologous to the E. coli DNA-dependent RNA polymerase β subunit) of the chloroplast DNA-dependent RNA polymerase was located on the chloroplast genome of Euglena gracilis distal to the rrnC ribosomal RNA operon. The complete nucleotide sequence of the gene was determined. The sequence includes 97 bp of the 5S rRNA gene, an intergenic spacer of 1264 bp, the rpoB gene of 4249 bp, 84 bp spacer and 67 bp of the rpoC1 gene. The rpoB gene is of the same polarity as the rRNA operons. The organization of the rpoB and rpoC genes resemble the E. coli rpoB-rpoC and higher plants chloroplast rpoB-rpoC1-rpoC2 operons. The Euglena rpoB gene (1082 codons) encodes a polypeptide with predicted molecular weight of 124,288. The rpoB gene is interrupted by seven Group III introns of 93, 95, 94, 99, 101, 110 and 99 bp, respectively, and a Group II intron of 309 bp. All other known chloroplast rpoB genes lack introns. All the exon-exon junctions were experimentally determined by cDNA cloning and sequencing or direct primer extension RNA sequencing. Transcripts from the rpoB locus were characterized by Northern hybridization. Fully-spliced, monocistronic rpoB mRNAs, as well as rpoB-rpoC1 and rpoB-rpoC1-rpoC2 mRNAs were identified. Unspliced intron-containing transcripts could not be detected in these experiments. The rpoB gene is the first gene in the RNA polymerase rpoB-rpoC1-rpoC2 transcription unit. The three genes are transcribed from a promoter located upstream the rpoB gene. The transcript is processed to mature monocistronic mRNAs. The relative abundance of the mono-, di- and tricistronic mRNAs appear to be similar in RNAs isolated from photoautotrophic, heterotrophic and dark grown cells. The mature 5'- and 3'-ends of the mature rpoB monocistronic transcripts were determined via S1 nuclease mapping and primer extension RNA sequencing. In addition, the sequence of the 23S rRNA from the rrnC operon and the intergenic spacer between the rrnA and rrnB operon were determined. Transcription initiation for the ribosomal RNA transcription unit was determined via Northern analysis and S1 nuclease mapping of chloroplast RNA that was in vitro 5'-end labeled. Two transcription initiation sites were mapped at positions +1 and -50 upstream the 16S rRNA gene. The 3'-ends of the rrnA/rrnB and rrnC 5S rRNA were determined using S1 nuclease protection experiments. The protected fragments were of identical size. The rpoB-C1-C2 DNA sequence has been submitted to EMBL, accession number X17171, and the 23S rRNA DNA sequence was given the number X13310.
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Jacobs, Michael A. "Identification and characterization of a chloroplast-encoded His-Asp signal transduction protein in the toxic stramenopile Heterosigma akashiwo /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/5250.
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Chebolu, Seethamahalakshmi. "EXPRESSION OF GAL/GALNAC LECTIN OF ENTAMOEBA HISTOLYTICA IN TRANSGENIC CHLOROPLASTS TO DEVELOP A VACCINE FOR AMEBIASIS." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3081.
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Amebiasis, also defined as invasive intestinal and extra intestinal amebiasis, is caused by Entameoba histolytica, an invasive protozoan parasite. World Health Organization (WHO) has reported that approximately 50 million people are infected each year causing an estimated 40 to 100 thousand deaths annually. Entameoba histolytica ranks only second to malaria as a protozoan cause of death. Amebiasis occurs world wide but people living in Central and South America, Africa and Asia are the majority to suffer from morbidity and mortality. The enteric parasite has no zoonotic reservoirs and insect vectors for its transmission and infects humans and non-human primates. Therefore, anti-amebic vaccine could completely eradicate the disease. Entamoeba histolytica invades tissue and causes the disease in series of events. The disease is caused when the cyst form of the parasite is ingested with contaminated food or water. After excysting in the small intestine to form the trophozoite, the parasite adheres to the colonic mucus and epithelial cells through interaction of Gal/GalNAc lectin, an amebic surface adhesin with the host glycoconjugates. The parasite then secrets the proteolytic enzymes that disrupt the intestinal mucus and epithelial barrier facilitating tissue penetration. The trophozoite then kills the host epithelial and immune cells. Also, it resists the host's immune response causing the prolonged infection called the invasive amebiasis and causes colon or liver abscess. The symptoms include gradual onset of abdominal pain, diarrhea and bloody stools. Also, it can form cysts that are excreted with stools to start new cycle. The parasite recognition of the host glycoconjugates plays an important role in the pathogenesis. Therefore, the Gal/GalNAc lectin could be a possible vaccine candidate. The Gal/GalNAc lectin is composed of a 260-kDa heterodimer of disulfide-linked heavy (170 kDa) and light (35 kDa) subunits, which is non-covalently associated with an intermediate sub-unit of 150 kDa. The only recognized Carbohydrate recognition domain (CRD) was found in the heavy sub-unit. The CRD of the lectin is the potential target for colonization blocking vaccines and drugs. Preliminary studies have shown that the recombinant fragments of cysteine-rich region of LecA (lectin) containing the CRD (carbohydrate recognition domain) of the GalNAc lectin conferred protection against amebiasis. Therefore, production of LecA in plants using chloroplast genetic engineering would result in low cost vaccine because of high expression levels of vaccine antigens, and elimination of the cold-chain (low temperature, storage & transportation), hospitals and health professionals for their delivery. The LecA protein was expressed in transgenic chloroplasts of Nicotiana tabacum var. Petit havana by transforming the chloroplast genome using the LecA gene (1755 bp) by homologous recombination. The pLD-CtV has trnI and trnA genes that are used as flanking sequences for homologous recombination and the constitutive 16s rRNA promoter to regulate transcription. The aadA gene conferring spectinomycin resistance has been used for selection and gene10 regulatory sequence from T7 bacteriophage to enhance translation. The chloroplast integration of LecA was confirmed by PCR and Southern blot analysis. The expression of LecA protein in transgenic chloroplasts was analyzed by immunoblot analysis using anti-LecA antibodies. Maximum expression levels of LecA up to 6.3 % of the total soluble protein were observed in the old leaves. The evaluation of the immune response in animal model is underway. This is the first report of expression of LecA in a plant system.M.S.
Department of Biology
Arts and Sciences
Biology
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Kalluri, Anila. "EXPRESSION OF CHOLERA TOXIN B SUBUNIT-ROTAVIRUS NSP4 ENTEROTOXIN FUSION PROTEIN IN TRANSGENIC CHLOROPLASTS." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3069.
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Rotavirus, the major cause of life-threatening infantile gastroenteritis, is a member of the Reoviridae family and is considered to be the single most important cause of virus-based severe diarrheal illness in infants and young children particularly 6 months to 2 years of age in industrialized and developing countries. Infection in infants and young children is often accompanied by severe life threatening diarrhea, most commonly following primary infection. Diarrhea is the major cause of death among children around the world. Responsible for 4 to 6 million deaths per year according to the World Health Organization (WHO), diarrhea is especially dangerous for infants and young children. Globally, it is estimated that 1.4 billion episodes of diarrhea occur in children less than five years of age annually. In the United States alone, rotavirus causes more than 3 million cases of childhood diarrhea each year, leading to an estimated 55,000 to 100,000 hospitalizations and 20 to 100 deaths. And is a major cause of mortality for children in developing countries with approximately one million deaths annually. Rotaviruses belong to the family Reoviridae and are spherical 70-nm particles. The virus genome contains 11 segments of double-stranded RNA, each encoding a viral capsid or nonstructural protein. The identification of a rotavirus nonstructural protein gene (NSP4) encoding a peptide, which functions both as a viral enterotoxin and as a factor involved in the acquisition of host cell membrane during virus budding from cells, provides a new approach for mucosal immunization. Protein expression through chloroplast transformation system offers a number of advantages like high level of transgene expression, transgene containment via maternal inheritance, lack of gene silencing and position effect due to site specific gene integration and also the possibility of multi gene engineering in single transformation event. It is also an environmentally friendly approach due to effective gene containment and lack of transgene expression in pollen. To achieve an enhanced immune response to rotavirus infection, a fusion gene encoding the cholera toxin B subunit linked to rotavirus enterotoxin 90 aa protein (CTB-NSP490) was introduced into transgenic chloroplast and was transformed into chloroplast genome of Nicotiana tabacum by homologous recombination. The chloroplast integration of CTB-NSP4(90) fusion gene was confirmed in transgenic tobacco plants by PCR analysis. Southern blot analysis further confirmed site specific gene integration and homoplasmy. Immunoblot analysis of transformed chloroplast confirmed the expression of CTBNSP490 fusion protein both in monomeric and pentameric forms that retained the binding affinity to the enterocytes GM1 ganglioside receptor. Expression levels of CTB-NSP4 protein was quantified by GM1 ganglioside binding ELISA assay; mature leaves expressed CTB-NSP4 fusion protein to upto 2.45 % in total soluble protein, 100-400 fold higher than nuclear expression which was only 0.006%-0.026%. Antibody titration and virus challenge experiments will be performed in mice at Loma Linda University to evaluate the antigenic and protective properties of the chloroplast derived CTB-NSP4 fusion protein.M.S.
Department of Molecular Biology and Microbiology
Burnett College of Biomedical Sciences
Molecular Biology and Microbiology
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Santos, Paula Cristina Bento Batista dos. "Molecular responses of Coffea spp. tolerance to low non-freezing temperatures." Doctoral thesis, ISA/UTL, 2010. http://hdl.handle.net/10400.5/3864.
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Doutoramento em Biologia - Instituto Superior de AgronomiaLow positive temperatures are of up most importance in tropical plant species, namely in Coffea spp., disturbing plant growth and metabolism, with impact on photosynthesis and yield. An integrated biochemical and molecular approach was used to analyze the cold impact and tolerance ability on photosynthesis of coffee plants, linked to modifications of the status of the antioxidative system, and chloroplast membrane lipids. Five coffee genotypes with contrasting cold sensitivity were used: Coffea canephora cv. Apoatã, C. arabica cv. Catuaí, C. dewevrei, Icatu (C. arabica x C. canephora) and Piatã (C. dewevrei x C. arabica). Determinations were performed along a slow cold imposition (to allow acclimation) from 25/20 ºC (day/night) down to 13/8 ºC, after exposure to 4o C (chilling) and in the rewarming period thereafter. Cold exposure strongly affected net photosynthesis in all genotypes, although stomatal limitations were not detected. Icatu revealed the lowest leaf loss, higher reinforcement of the antioxidative system, qualitative changes in chloroplast membrane lipids and regulation of some key genes. Altogether these responses indicate a better ability of this genotype to cope with low positive temperatures
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McKenzie, Belinda, and s9907915@student rmit edu au. "Heterologous expression of cellulase enzymes in transplastidic Nicotiana tabacum cv. Petit Havana." RMIT University. Applied Sciences, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080805.120923.
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Extensive research into enzyme-induced bio-conversion of lignocellulose to soluble sugars has been conducted and research continues in this area. Several approaches have been taken to attempt to alleviate the economic problems associated with utilisation of lignocellulose in fuel ethanol production. By expressing cellulase genes in planta, it is hoped that the cost of enzyme-mediated hydrolysis of cellulose to its soluble sugar monomers, will be reduced. Some accomplishments have been made in this area using nuclear genetic transformation (Abdeev et al., 2003; Abdeev et al., 2004; Austin-Phillips et al., 1999; Biswas et al., 2006; Dai et al., 2000a,b; Dai et al., 2005; Jin et al., 2003; Kawazu et al., 1999; Sakka et al., 2000; Ziegelhoffer et al., 1999; Ziegelhoffer et al., 2001; Ziegler et al., 2000), but more research is required to bring the levels of cellulase enzyme expression in plants to levels that will make the process economically competitive. Chloroplasts of N. tabacum were selected as a target for transformation for high level expression due to their extremely high rates of transcription and translation. These were transformed with two genes, the e1 gene from A. cellulolyticus, and the cbh1 gene from T. reesei. Further aims included the investigation of the effects of using different promoters, and the novel use of both nuclear and chloroplast-based expression in a single plant, on the level of protein production in the heterologous host. Heterologous expression of the cbh1 gene was not successful. This is thought to be due to toxicity of the protein in a prokaryotic environment. Future studies should focus on trying to avoid this toxicity by targeting of the chloroplast-expressed enzyme to specific tissues, such as the thylakoid membrane, for containment, creating a codon-optimised synthetic gene that better mimics the codon usage of the plant to be used for expression, or placing the expression under a reactive cascade that is only activated upon exposure to an external trigger. Heterologous expression of the full length gene for E1 from A. cellulolyticus was successful. Chloroplast homology vectors under the constitutive promoter Prrn, and the inducible promoter T7, were constructed and these were used to successfully transform N. tabacum cv. Petit Havana chloroplasts. Stable transgenic plants were produced and evaluated by a variety of means, with the heterologously expressed enzyme showing activity against the soluble substrate analogue MUC of up to 3122 ± 466 pmol 4-MU/mg TSP/min and an E1 accumulation level of up to 0.35% ± 0.06 of the total soluble protein. Lastly, chloroplast transformation was combined with nuclear transformation to create novel dual-transgenic plants simultaneously expressing E1 from both the nuclear and chloroplast genomes. The combination of these technologies was very successful, with the heterologously expressed enzyme showing activity against the soluble substrate analogue MUC of up to 35706 ± 955 pmol 4-MU/mg TSP/min and an E1 accumulation level of up to 4.78% ± 0.13 of the total soluble protein, and provides a new approach for increasing the accumulation levels of plant-produced cellulase enzymes.
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Knight, Julie Sylvia. "The isolation, characterization and expression of the gene encoding the chloroplast Rieske iron-sulphur protein of Arabidopsis thaliana." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338309.
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Lloyd, Bethany. "Expression of Lipase from Mycobacterium tuberculosis in Nicotiana tobacum and Lactuca sativa Chloroplasts." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5406.
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Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis (M. tuberculosis), is a global threat and the leading cause of death among individuals infected with HIV. TB treatment requires multi-drug cocktails, due to the increasing rates of drug resistance of the bacterium. With multi-drug cocktails, strains have been documented to be resistant to all major drugs in the fight against TB. Since the strains are drug resistant, it calls for an increasing need for vaccine and treatment development for the purpose of preventing and managing the disease. The most widely distributed vaccine against TB is Bacillus Calmette-Gue&"180;rin (BCG). Apart from being ineffective in certain individuals, BCG offers only a limited timeframe of protection, is unable to serve as a booster for extending this timeframe and due to the intradermal route of administration requires costly refrigeration and syringes. LipY protein, a M. tuberculosis cell wall lipase, may play a potential role as not only a drug target but a potential vaccine antigen. LipY is known to be up-regulated during both active infection and dormancy. In a previous study, sera from TB patients had shown an IgG and IgM response against it. In this study transplastomic Lactuca sativa and Nicotiana tabacum plants were generated by transforming the chloroplasts through the particle delivery system with pLsDv-LipY and pLD-LipY vectors respectively. The vectors were flanked by the native trnI and trnA gene sequence to facilitate homologous recombination into the chloroplast genome. The vector also contained the 16S rRNA promoter, the selectable marker gene, aadA for specitinomycin resistance, the rbcL untranslated region, the LsPpsbA (PpsbA in N. tabacum) promoter, and LsTpsbA (tpsbA in N. tabacum) untranslated region. Site specific integration of the LipY gene into the chloroplast genome was confirmed by PCR. Homoplasmy of transplastomic plants was confirmed by Southern blot analysis. These plants showed normal growth and were fertile, producing seeds. Once germinated, these seeds did not show Mendelian segregation of the transgene. Immunoblot analysis was performed to analyze the expression of the LipY protein. A 40kDa protein was produced in E.coli, and a 25kDa protein was produced in chloroplasts; a cleaved product in chloroplasts is still valuable as an antigen for vaccine production. Future studies will include testing this chloroplast derived antigen in animal models for vaccine development. ?M.S.
Masters
Molecular Biology and Microbiology
Medicine
Biotechnology
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Zhou, Dao Xiu. "Organisation et expression de gènes chloroplastiques et nucléaires codant pour des protéines ribosomiques du chloroplaste d'épinard." Grenoble 1, 1988. http://www.theses.fr/1988GRE10113.
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Xu, Duorong [Verfasser], and Tatjana [Akademischer Betreuer] Kleine. "The contribution of extrachloroplastic factors and plastid gene expression to chloroplast development and abiotic stress tolerance / Duorong Xu ; Betreuer: Tatjana Kleine." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1216039232/34.
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Nityanandam, Ramya. "Expression and functional evaluation of exendin 4 fused to cholera toxin B subunit in tobacco chloroplast to treat type 2 diabetes." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4815.
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The prevalence of type 2 diabetes has been steadily increasing around the globe. Glucagon like peptide (GLP-1), a powerful incretin increases insulin secretion in a glucose dependent manner. But GLP-1 is subjected to rapid enzymatic degradation (half-life: 2 min in circulation). The commercially available GLP-1 analog, exenatide has a longer half life with potent insulinotropic effects (about 2.4 hr) which requires cold storage and daily subcutaneous injections. In this study, exendin 4 (EX4), lizard derived GLP-1R agonist, was expressed as cholera toxin B subunit (CTB)-fusion protein in chloroplasts of tobacco to facilitate transmucosal delivery in the gut by utilizing the ability of CTB pentamer to bind the GM1 receptors on the intestinal epithelium and to bioencapsulate EX4 within plant cells to confer protection in the digestive system. The LAMD tobacco leaves were bombarded with chloroplast vectors expressing modified EX4. The transgene integration was confirmed by PCR analysis and Southern blot analysis. Densitometric analysis revealed expression level of the protein varied from 9-13% of the total leaf protein depending on the developmental stage and time of harvest. The pentameric structure and functionality of CTB-EX4 fusion protein was confirmed by CTB-GM1 binding assay. The effect of transplastomic protein on insulin secretion was tested in beta]-TC6, a mouse pancreatic cell line. The plant derived CTB-EX4, partially purified with anti-CTB antibody conjugated protein A beads, showed the increase of insulin ~ 2.5 fold increase when compared to untreated cells. The transplastomic protein showed a linear increase in insulin secretion comparable to the commercially available EX4. The current cost of treatment with EX4 varies between $1800-$2200, annually. Production of functional EX4 in plants should facilitate low cost orally deliverable form of this drug for treatment of type 2 diabetes.ID: 031001317; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Title from PDF title page (viewed March 26, 2013).; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 35-40).
M.S.
Masters
Molecular Biology and Micro
Medicine
Biotechnology
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Thomas, Franck. "Expression des gènes rpl23, rpl2, rps19 et rps19' du génome chloroplastique d'épinard : identification des produits de quelques gènes de protéines ribosomiques." Grenoble 1, 1987. http://www.theses.fr/1987GRE10171.
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Le genome chloroplastique d'epinard est constitue d'une molecule d'adn circulaire (140 kbp) organisee en 4 regions: une sequence unique (lsc) et une petite sequence unique (ssc) separees par deux regions inversees repetees (ira et irb). L'expression des genes rp12, rps19 et rps19' est etudie. Les techniques de clonage et de cartographie a la nuclease s1 ont peris de montrer que le gene rps19' n'est pas exprime "in vivo" dans le chloroplaste en raison de la co-transcription sur l'autre brin des genes psba et trn h-gug. Les genes rp12 et rps19 codent respectivement pour les proteines ribosomiques chloroplastiques d'epinard l4 et s23 fortement homologues aux l2 et s19 d'e. Coli
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Christopher, David Alan. "Structure and expression of a Euglena gracilis chloroplast transcription unit encoding 11 ribosomal protein genes, a tRNA gene and a 2.8 kb intergenic region." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184937.
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The structure and expression of a novel Euglena gracilis chloroplast ribosomal protein operon was studied by gene mapping, molecular cloning, nucleotide sequencing primer extension and Northern analyses. The nucleotide sequence (12,240 bp) was determined for 100% of both strands encoding the 12 genes, rpl23 - rpl2 - rps19 - rpl22 - rps3-(2.8 kb region)- rpl16 - rpl14 - rpl5 - rps8 - rpl36 - trnI - rps14. The gene organization resembles the S10 and spc ribosomal protein operons of E. coli. The rpl5 gene was a new chloroplast gene not previously reported for any chloroplast genome nor described as a nuclear gene. The presence of numerous introns and an unusual 2.8 kb rps3-rpl16 intercistronic region were additional features that were unparalleled in other chloroplast DNAs. At least 15 introns were identified in the genes. Evidence is presented from primer extension analysis of chloroplast RNA for the correct in vivo splicing of six of the introns. Two introns within rps8 flanked an 8 bp exon, the smallest exon yet characterized in a chloroplast genome. Four introns shared structural properties with group II organelle introns. The remaining 11 introns were defined as new category of organelle intron, now designated "group III." The presence of additional introns in several intercistronic regions is proposed. Conserved regions in the predicted polypeptides were identified from the alignments with related proteins from other chloroplasts and bacteria. Evidence from Northern hybridization experiments with gene-specific probes supported the interpretation that 11 ribosomal protein genes, the 2.8 kb rps3-rpl16 intercistronic region and trnI were co-transcribed and encoded in a single operon. The co-transcription of genes coding for proteins and a tRNA is a novel finding for a chloroplast operon. Several stable polycistronic transcripts were identified, including a common 8.3 kb pre-mRNA. Stepwise processing pathways proposed for the mRNAs are described. Most mRNAs appeared to be fully spliced. The 5$\sp\prime$ ends of mRNAs for the first gene in the operon, rpl23, were mapped by primer extension. Plastid mRNAs from dark and light grown Euglena were analyzed on Northern blots.
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Lagrange, Thierry. "Evolution, structure et expression du gène nucléaire rpl21 codant pour la protéine ribosomique plastidiale cL21 d'épinard." Grenoble 1, 1993. http://www.theses.fr/1993GRE10152.
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Le ribosome plastidial presente une synthese accrue dans les cellules photosynthetiques, et une expression basale dans les autres types cellulaires. C'est donc afin de comprendre par quels mecanismes, les genes nucleaires qui codent pour des proteines ribosomiques (p. R. ) plastidiales repondent a cette demande traductionnelle tres variable que nous avons isole chez spinacia oleracea un gene nucleaire modele, le gene rpl21. Nous avons tout d'abord caracterise un adnc codant pour une p. R. Plastidiale. La sequence primaire deduite de cette proteine presente une homologie avec la sequence de la p. R. L21 d'e. Coli. Cette proteine a ete nommee cl21. Les implications evolutives sur l'origine de la proteine cl21 d'epinard, que ces resultats suggerent, sont discutees. Dans la suite de ce travail, nous avons montre que la proteine cl21 est codee par un unique gene nucleaire, nomme rpl21. Nous avons ensuite clone et sequence la totalite de la region codante ainsi que la region 5 regulatrice du gene rpl21. L'analyse de la repartition des messagers rpl21 par la technique de northern nous a permis d'observer une accumulation preferentielle de ces messagers dans les feuilles par rapport aux racines. Cette expression variable suivant les organes de la plante a pu etre associee a la presence de transcrits alternatifs, nommes p1 et p2. Des experiences d'expression transitoire suggerent que ces deux transcrits proviennent chacun d'une initiation de transcription. L'adaptation de l'expression des genes nucleaires de proteines ribosomiques plastidiales aux contraintes fonctionnelles du systeme vegetal est discutee. Dans la derniere partie de ce travail, l'analyse systematique de l'organisation du promoteur du gene rpl21 nous a permis de mettre en evidence plusieurs elements cis qui sont impliques dans l'activation transcriptionnelle de ce gene. Les roles potentiels de ces elements dans l'expression de ces genes et dans le developpement du chloroplaste sont discutes
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Cheng, Qi. "Studies in the expression and function of Klebsiella pneumoniae nitrogenase iron protein in the chloroplast of the eukaryotic unicellular green algae - Chlamydomonas reinhardtii." Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302041.
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Franzetti, Bruno. "Structure, fonction et expression de la protéine ribosomique chloroplastique CS1." Grenoble 1, 1992. http://www.theses.fr/1992GRE10099.
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Le controle de l'initiation de la traduction est une etape importante de l'expression des genes chloroplastiques et fait intervenir, chez e. Coli, la proteine ribosomique (proteine-r) s1. Afin d'etudier l'etape d'initiation de la traduction chez le chloroplaste, nous avons caracterise chez spinacia oleracea une proteine (cs1) apparentee a la proteine s1. Nous avons isole un adnc codant pour le precurseur de la proteine-r cs1. Cs1 est considerablement plus courte que sa contrepartie bacterienne. Un noyau central homologue se compose de trois repetitions degenerees qui presentent de l'homologie principalement avec le domaine de liaison a l'arn de la proteine s1 d'e. Coli. Cs1 a ete surproduite dans e. Coli et purifiee. Nous avons etudie les proprietes de liaison a l'arn de la proteine cs1 au sein de la sous-unite ribosomique 30s et de la proteine isolee. Nous montrons que cs1 joue un role actif dans la liaison des arnm durant l'initiation de la traduction. Les implications de ces resultats pour la comprehension du systeme traductionnel du chloroplaste sont discutees. Dans la seconde partie de ce travail, nous avons montre que l'arnm codant pour la proteine-r cs1 est synthetise tres precocement durant les premieres etapes du developpement des plantes et est accumule meme en absence de lumiere. Nous avons clone et sequence la totalite de la region codante ainsi que la region 5 regulatrice du gene nucleaire unique (rps1) codant pour cs1. Nous avons observe la presence de deux departs de transcription. L'arnm le plus long code par le gene rps1 est specifiquement transcrit dans les feuilles. Ces resultats sont a relier a une accumulation differentielle de l'arnm cs1 dans les racines et dans les feuilles. Ces observations nous amenent a conclure que le gene de menage rps1 est regule transcriptionnellement de maniere tissu-specifique
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Barsoum, Mirna Verfasser], Rainer [Akademischer Betreuer] [Fischer, and Ralph [Akademischer Betreuer] Panstruga. "Expression and characterization of single elements from Chlamydomonas reinhardtii CO2 concentration mechanism in the chloroplast of C3 plants / Mirna Barsoum ; Rainer Fischer, Ralph Panstruga." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1161412689/34.
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Barsoum, Mirna [Verfasser], Rainer [Akademischer Betreuer] Fischer, and Ralph [Akademischer Betreuer] Panstruga. "Expression and characterization of single elements from Chlamydomonas reinhardtii CO2 concentration mechanism in the chloroplast of C3 plants / Mirna Barsoum ; Rainer Fischer, Ralph Panstruga." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1161412689/34.
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Wang, Eu Sheng. "Construction and molecular characterisation of an improved chloroplast transformation vector system as a versatile delivery and expression platform for in-vitro propagated Nicotiana benthamiana." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/30486/.
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The objective of this study is to develop a versatile vector system for the delivery and expression of transgenes in the chloroplast genome of N. benthamiana. The successful advent of such a system would vastly streamline the construction process of chloroplast transformation vectors for the expression of recombinant proteins, such as vaccine candidates, in the chloroplasts of N. benthamiana. Transgenes targeted to the chloroplasts of higher plants are expected to be expressed at considerably higher levels as compared to nuclear expression, resulting in more significant accumulation of recombinant proteins. In this study, a 2-part chloroplast transformation vector system was developed and two new GFP vector prototypes, pEXPR-G and pEXPR-UG were generated for preliminary evaluation of functionality. The aadA and GFP expression cassettes of pEXPR-G and pEXPR-UG were evaluated in E. coli prior to actual delivery into N. benthamiana via particle bombardment. Particle bombardment parameters were optimised with particular emphasis on minimising excessive damage to the target tissue in order to facilitate the recovery of antibiotic resistant shoots and calli following transformation. To further evaluate the versatility of the developed system for the expression of vaccine antigens, recombinant vectors, pEXPR-HA and pEXPR-NA were constructed for the delivery of hemagglutinin (HA) and neuraminidase (NA) genes of avian influenza strain H5N1 into the chloroplast genome of N. benthamiana. Experimental results indicated that pEXPR-G and pEXPR-UG were fundamentally functional in E. coli and both the aadA and GFP expression cassettes were active, allowing the bacteria to withstand 500mg/l spectinomycin and express the transgene of interest at the protein level. Similar results were also observed in transplastomic N. benthamiana transformed with pEXPR-UG and pEXPR-NA. In essence, the developed 2-part chloroplast transformation vector system was found to be highly versatile and could be conveniently applied for the construction of transformation vectors for the delivery and expression of HA and NA in the chloroplast of N. benthamiana.
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Liebers, Monique [Verfasser], Ralf Gutachter] Oelmüller, Thomas [Gutachter] [Pfannschmidt, and Karin [Gutachter] Krupinska. "Spatio-temporal expression of nuclear-encoded proteins associated to the plastid-encoded RNA polymerase essential for chloroplast biogenesis in Arabidopsis thaliana L. / Monique Liebers ; Gutachter: Ralf Oelmüller, Thomas Pfannschmidt, Karin Krupinska." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/1177597675/34.
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Teyssier, Emeline. "Caractérisation de protéines de l'enveloppe des chloroplastes d'épinard." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10303.
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Les plastes forment une vaste famille d'organites capables de subir des phenomenes de differenciation et/ou d'interconversion. L'enveloppe apparait comme la seule structure membranaire permanente du plaste. Malgre l'importance des fonctions de l'enveloppe, la caracterisation des proteines constituant ses 2 membranes est rudimentaire. Nous avons analyse 3 proteines majeures de l'enveloppe des chloroplastes d'epinard : e10 (10 kda) et e24 (24 kda) sont des marqueurs de la membrane externe, e37 (37 kda), un marqueur de la membrane interne. La fonction des trois proteines etait inconnue lorsque nous avons commence notre analyse. Nous avons quantifie les proteines e10, e24 et e37 et les arnm correspondants dans differents organes, au cours du developpement de plantules d'epinard. L'analyse de l'expression d'autres proteines du chloroplaste, comme le transporteur de triose phosphate/phosphate nous a servi de reference. Les proteines e10, e24, e37 et le transporteur de triose phosphate/phosphate sont exprimes de facon preferentielle dans les organes foliaires, etioles ou non. De plus l'expression de la proteine e10 apparait correlee a la phase de croissance de la feuille. Nous avons isole et analyse un adnc codant pour la proteine e24 par criblage d'une banque d'expression. La sequence primaire de la proteine e24 a ainsi pu etre determinee. Nous avons etudie la topologie membranaire de la proteine par une approche immunologique : la proteine e24 est ancree dans la membrane par sa region c-terminale, sa region n-terminale etant accessible a partir du cytosol. La sequence primaire de la proteine e37 revele des motifs conserves chez toutes les methyltransferases et des experiences de photomarquage ont montre que la proteine e37 d'epinard est capable de lier specifiquement la s-adenosyl-methionine. La proteine e37 est donc vraisemblablement responsable d'une activite methyltransferase dans l'enveloppe. Nous recherchons actuellement le substrat methyle par la proteine e37.
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Badillo, Corona Jesús Agustín. "Expression of foreign antigens in tobacco chloroplasts." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613376.
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Borchers, Anne-Marie Inka. "Expression of rotaviral VP6 in tobacco chloroplasts." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611089.
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Kuntz, Marcel. "Etude de la structure et de l'expression des genomes plastidiaux et du transport des proteines dans les chloroplastes." Université Louis Pasteur (Strasbourg) (1971-2008), 1989. http://www.theses.fr/1989STR13012.
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Etude des genes de trna d'organistes photosynthetiques et determination des sequences nucleotidiques des genes du trna**(t4r)(ggu), trna**(glu)(uuc) et trna**(tyr)(gua) chloroplastiques de feve et des genes des trna**(glu)(uuc), trna**(leu)(uaa), trna**(ser)(gga) et trna**(gly)(ggc) des cyanelles de cyanophora paradoxa. Un intron de classe i a ete mis en evidence dans le gene codant pour le trna**(leu)(uaa) de cyanelles. A l'aide des techniques de fusion de genes et de transformation des plantes, il est apparu que le peptide transit de la pente sous unite de la rubisco permet le transport efficace d'une proteine etrangere dans les chloroplastes. La regulation de l'expression des genes plastidiaux s'effectue donc au niveau de la traduction
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Boehm, Christian Reiner. "Gene expression control for synthetic patterning of bacterial populations and plants." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267842.
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The development of shape in multicellular organisms has intrigued human minds for millenia. Empowered by modern genetic techniques, molecular biologists are now striving to not only dissect developmental processes, but to exploit their modularity for the design of custom living systems used in bioproduction, remediation, and regenerative medicine. Currently, our capacity to harness this potential is fundamentally limited by a lack of spatiotemporal control over gene expression in multicellular systems. While several synthetic genetic circuits for control of multicellular patterning have been reported, hierarchical induction of gene expression domains has received little attention from synthetic biologists, despite its fundamental role in biological self-organization. In this thesis, I introduce the first synthetic genetic system implementing population-based AND logic for programmed hierarchical patterning of bacterial populations of Escherichia coli, and address fundamental prerequisites for implementation of an analogous genetic circuit into the emergent multicellular plant model Marchantia polymorpha. In both model systems, I explore the use of bacteriophage T7 RNA polymerase as a gene expression engine to control synthetic patterning across populations of cells. In E. coli, I developed a ratiometric assay of bacteriophage T7 RNA polymerase activity, which I used to systematically characterize different intact and split enzyme variants. I utilized the best-performing variant to build a three-color patterning system responsive to two different homoserine lactones. I validated the AND gate-like behavior of this system both in cell suspension and in surface culture. Then, I used the synthetic circuit in a membrane-based spatial assay to demonstrate programmed hierarchical patterning of gene expression across bacterial populations. To prepare the adaption of bacteriophage T7 RNA polymerase-driven synthetic patterning from the prokaryote E. coli to the eukaryote M. polymorpha, I developed a toolbox of genetic elements for spatial gene expression control in the liverwort: I analyzed codon usage across the transcriptome of M. polymorpha, and used insights gained to design codon-optimized fluorescent reporters successfully expressed from its nuclear and chloroplast genomes. For targeting of bacteriophage T7 RNA polymerase to these cellular compartments, I functionally validated nuclear localization signals and chloroplast transit peptides. For spatiotemporal control of bacteriophage T7 RNA polymerase in M. polymorpha, I characterized spatially restricted and inducible promoters. For facilitated posttranscriptional processing of target transcripts, I functionally validated viral enhancer sequences in M. polymorpha. Taking advantage of this genetic toolbox, I introduced inducible nuclear-targeted bacteriophage T7 RNA polymerase into M. polymorpha. I showed implementation of the bacteriophage T7 RNA polymerase/PT7 expression system accompanied by hypermethylation of its target nuclear transgene. My observations suggest operation of efficient epigenetic gene silencing in M. polymorpha, and guide future efforts in chassis engineering of this multicellular plant model. Furthermore, my results encourage utilization of spatiotemporally controlled bacteriophage T7 RNA polymerase as a targeted silencing system for functional genomic studies and morphogenetic engineering in the liverwort. Taken together, the work presented enhances our capacity for spatiotemporal gene expression control in bacterial populations and plants, facilitating future efforts in synthetic morphogenesis for applications in synthetic biology and metabolic engineering.
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Houlné, Guy. "Structure et expression des genes codant pour les apoproteines des antennes collectrices de photons ps2 et ps1 chez euglena gracilis." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13169.
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Cherukumilli, Sri. "Expression of Human Interferon in Transgenic Tobacco Chloroplasts." Honors in the Major Thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/747.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucfBachelors
Burnett College of Biomedical Sciences
Molecular Biology and Microbiology
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Bégot, Laurent. "Caractérisation du mutant dal1-2 d'Arabidopsis thaliana, affecté dans le développement précoce du chloroplaste." Université Joseph Fourier (Grenoble ; 1971-2015), 1999. http://www.theses.fr/1999GRE10054.
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Le mutant d'arabidopsis thaliana dal1-2, etiquete par un element transposable ac, est bloque precocement dans le developpement du chloroplaste. Son etude phenotypique a permit de mettre en evidence une couleur des feuilles variant du jaune au vert clair, au cours de son developpement. Morphologiquement, des coupes histologiques de feuilles montrent une desorganisation de la couche palissadique mesophyllienne. Le nombre de chloroplastes par cellule est plus important chez le mutant compare avec le sauvage mais leur taille est plus petite. La structure des chloroplastes par microscopie electronique a transmission montre une desorganisation et une quantite reduite des membranes thylacoidiennes. Les dosages realises sur les chlorophylles, carotenoides et lipides indiquent une forte reduction quantitative de ces molecules chez le mutant. La respiration chez le mutant est normale mais la photosynthese est residuelle pour un stade de developpement avance du mutant. Dal1-2 n'est pas affecte dans la skotomorphogenese. Au niveau genetique, l'isolement de l'adnc et du gene ont ete realises. L'expression du gene dal est absente chez le mutant. Une seule copie du gene dal est presente dans le genome nucleaire d'arabidopsis thaliana et celui-ci appartient a une famille de genes. L'expression de dal est elevee dans les boutons floraux et les fleurs. La proteine dal contient une sequence d'adressage chloroplastique et est importee dans le chloroplaste. L'analyse de l'expression de genes impliques dans le developpement des organites a permit de montrer clairement que la coordination de l'expression de genes nucleaires et chloroplastiques est toujours assuree chez le mutant dal1-2. L'expression des genes nucleaires de proteines ribosomiques est inchangee dans le mutant alors que l'expression des genes photosynthetiques cab et rbcs est reduite. Globalement, l'expression des genes mitochondriaux montre un niveau d'expression normal. Par contre, l'expression de tous les genes chloroplastiques testes est fortement reduite. L'analyse de l'expression de l'adnr 16s chloroplastique revele la presence de 50% d'arnr 16s non matures. Une explication possible etant que la proteine dal soit impliquee dans la maturation post-transcriptionnelle des arnr 16s. Ainsi, l'absence de la proteine dal conduirait a une chute de l'assemblage des ribosomes 70s, et par consequent a une perte de l'integrite chloroplastique.