Thematische Bibliographien / Polytene chromosome

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Auswahl der wissenschaftlichen Literatur zum Thema „Polytene chromosome“

Autor: Grafiati

Veröffentlicht am 18. Mai 2024

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Zeitschriftenartikel zum Thema "Polytene chromosome"

Bedo, D. G. „Polytene chromosome mapping in Ceratitis capitata (Diptera: Tephritidae)“. Genome 29, Nr. 4 (01.08.1987): 598–611. http://dx.doi.org/10.1139/g87-101.

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Polytene chromosome reference maps of the five autosomes of Ceratitis capitata from male pupal orbital bristle trichogen cells are presented and a correlation is established between two of them and the two largest of the five autosomes in the haploid mitotic complement. Characteristic features of each chromosome are described identifying areas that are difficult to analyze and noting the existence of common alternative band expression. A quantitative analysis of the mitotic karyotype of C. capitata indicates that the two smallest autosome pairs cannot be reliably distinguished. This may present problems with future attempts to establish homologies between the remaining mitotic and polytene chromosomes. A comparison of polytene chromosome banding patterns from salivary gland and trichogen cells failed to find any homologous regions, or even to identify homologous chromosomes. The banding differences are not explained by variation in puffing patterns, heterochromatin expression, or polyteny levels, but appear to reflect fundamental differences in banding patterns of the chromosomes in each tissue. Key words: Ceratitis capitata, polytene chromosome map, mitotic chromosome measurements.

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Zacharopoulou, A. „Polytene chromosome maps in the Medfly Ceratitis capitata“. Genome 33, Nr. 2 (01.04.1990): 184–97. http://dx.doi.org/10.1139/g90-030.

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Polytene chromosome maps of the five autosomes from salivary gland cells in Ceratitis capitata are presented, and the more characteristic features of each element are described. The correlation of the polytene elements to miotic chromosomes and linkage groups is established by using various Y-autosome and autosome-autosome translocation lines. Two loci, dp (black pupal case) and w (white pupal case), are mapped to the third and fifth chromosome, respectively. In addition to the polytene maps presented, some extra figures of specific chromosomal regions are given for easier identification of each polytene element.Key words: polytene chromosome maps, Ceratitis capitata.

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Garcia-Martinez, V., E. Hernandez-Ortiz, C. S. Zepeta-Cisneros, A. S. Robinson, A. Zacharopoulou und G. Franz. „Mitotic and polytene chromosome analysis in the Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae)“. Genome 52, Nr. 1 (Januar 2009): 20–30. http://dx.doi.org/10.1139/g08-099.

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The present study constitutes the first attempt to construct a polytene chromosome map of an Anastrepha species, Anastrepha ludens (Loew), a major agricultural pest. The mitotic karyotype has a diploid complement of 12 acrocentric chromosomes, including five pairs of autosomes and an XX/XY sex chromosome pair. The analysis of salivary gland polytene chromosomes has shown a total number of five polytene elements that correspond to the five autosomes. The characteristic features and the most prominent landmarks of each chromosome are described. By comparing chromosome banding patterns, the possible chromosomal homology between A. ludens and Ceratitis capitata (Wiedemann) is presented. This work shows that polytene maps of A. ludens are suitable for cytogenetic studies in this species and may be used as reference for other Anastrepha species, most of which are also serious agricultural pests.

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Zhao, J. T., M. Frommer, J. A. Sved und A. Zacharopoulou. „Mitotic and polytene chromosome analyses in the Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae)“. Genome 41, Nr. 4 (01.08.1998): 510–26. http://dx.doi.org/10.1139/g98-053.

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The Queensland fruit fly, Bactrocera tryoni, like the Mediterranean fruit fly, Ceratitis capitata, has a diploid complement of 12 chromosomes, including five pairs of autosomes and a XX/XY sex chromosome pair. Characteristic features of each chromosome are described. Chromosomal homology between B. tryoni and C. capitata has been determined by comparing chromosome banding pattern and in situ hybridisation of cloned genes to polytene chromosomes. Although the evidence indicates that a number of chromosomal inversions have occurred since the separation of the two species, synteny of the chromosomes appears to have been maintained.Key words: tephritid fruit fly, Bactrocera tryoni, polytene chromosomes, in situ hybridisation, chromosomal homology.

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Bedo, D. G. „Polytene and mitotic chromosome analysis in Ceratitis capitata (Diptera; Tephritidae)“. Canadian Journal of Genetics and Cytology 28, Nr. 2 (01.04.1986): 180–88. http://dx.doi.org/10.1139/g86-025.

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Polytene chromosomes were found in several larval and pupal tissues of the Medfly, Ceratitis capitata, during a search for chromosomes suitable for detailed cytological analysis. Well-banded highly polytene chromosomes, which could be adequately separated and spread, were found in trichogen cells of the spatulate superior orbital bristles of male pupae. These chromosomes proved suitable for full polytene analysis. Thoracic trichogen cells of both male and female pupae also contain useful polytene chromosomes, although they are considerably thinner and thus more difficult to analyze. Contrasting with those in pupal trichogen cells, the chromosomes in the salivary glands, Malphighian tubules, midgut, hindgut, and fat body of larvae and pupae were difficult to prepare because of high levels of ectopic pairing and chromosome fragmentation. In hindgut preparations partial separation of up to three chromosomes was achieved, but in all other tissues no useful chromosome separation was possible. In trichogen polytene cells, five banded chromosomes and a prominent heterochromatic network associated with a nucleolus are found. The mitotic chromosomes respond to C- and Q-banding and silver staining with considerable variation. This is especially so in the X chromosome, which displays an extensive array of bands following both Q-banding and silver staining. Comparison of Q-banded metaphase and polytene chromosomes demonstrates that the five autosomes are represented by conventional polytene chromosomes, while the sex chromosomes are contained in the heterochromatic net, most of which fluoresces strongly. This suggests that the Q-bands of the mitotic X chromosome are replicated to a greater extent than the nonfluorescent material in polytene cells. This investigation shows C. capitata to have excellent cytological material for both polytene and mitotic analysis.Key words: Ceratitis capitata, Medfly, chromosomes (polytene), banding (chromosome).

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Bedo, D. G. „Polytene chromosomes of the Old World screwworm fly (Chrysomya bezziana) and its evolutionary relationships with Lucilia cuprina and Cochliomyia hominivorax (Diptera: Calliphoridae)“. Genome 35, Nr. 2 (01.04.1992): 294–303. http://dx.doi.org/10.1139/g92-045.

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Standard polytene chromosome maps for the Old World screwsworm fly, Chrysomya bezziana, are presented. Good quality polytene chromosomes obtainable from pupal trichogen cells allow detailed analysis of autosomal euchromatin. The sex chromosomes are represented by irregular heterochromatic structures resembling those described previously in trichogen polytene chromosomes of the Australian sheep blowfly, Lucilia cuprina. A high degree of homology with the banding pattern of L. cuprina polytene chromosomes allowed direct recognition of approximately 60% of the L. cuprina complement in the C. bezziana maps. A further 13% may be homologous. The extensive homology observed is discussed in relation to the rate of chromosome rearrangement and conservation of karyotype elements in the evolution of Calliphorid flies. The observed conservation in polytene banding patterns should facilitate construction of phylogenies over a number of generic groups.Key words: Chrysomya bezziana, screwworm, polytene map, chromosome homology.

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Liang, Jiangtao, Simon M. Bondarenko, Igor V. Sharakhov und Maria V. Sharakhova. „Obtaining Polytene, Meiotic, and Mitotic Chromosomes from Mosquitoes for Cytogenetic Analysis“. Cold Spring Harbor Protocols 2022, Nr. 12 (05.08.2022): pdb.prot107872. http://dx.doi.org/10.1101/pdb.prot107872.

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Chromosome visualization is a key step for developing cytogenetic maps and idiograms, analyzing inversion polymorphisms, and identifying mosquito species. Three types of chromosomes—polytene, mitotic, and meiotic—are used in cytogenetic studies of mosquitoes. Here, we describe a detailed method for obtaining high-quality polytene chromosome preparations from the salivary glands of larvae and the ovaries of females forAnophelesmosquitoes. We also describe how to obtain mitotic chromosomes from imaginal discs of fourth-instar larvae and meiotic chromosomes from the testes of male pupae for all mosquitoes. These chromosomes can be used for fluorescence in situ hybridization (FISH), a fundamental technique in cytogenetic research that is used for physical genome mapping, detecting chromosomal rearrangements, and studying chromosome organization.

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Shahjahan, Reza M., und Farzana Yesmin. „Polytene chromosome maps of the melon fly Bactrocera cucurbitae (Diptera: Tephritidae)“. Genome 45, Nr. 6 (01.12.2002): 1167–74. http://dx.doi.org/10.1139/g02-081.

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Standard photographic maps of the polytene chromosomes are presented for the melon fly Bactrocera cucurbitae, a serious pest of fleshy fruits and vegetables. Five larval salivary gland polytene chromosomes (10 polytene arms) were isolated, and their characteristic features and landmarks have been recognized. Banding patterns of each of the polytene arms are presented, where variation in band intensity and puffs appear to reflect fundamental differences in chromosomes. The whole polytene genome has been typically mapped by dividing it into 100 sections and the subsections were lettered. The mitotic chromosomes of larval brain ganglia are also examined, five pairs of autosomes and an XX/XY sex chromosome pair. In addition, a heterochromatic mass corresponding to the sex chromosomes are observed in the polytene nuclei of salivary gland tissue. This investigation showed that B. cucurbitae has excellent cytological material for polytene chromosome analysis and proved to be very useful for obtaining more detailed genetic information on the pest's natural populations.Key words: Bactrocera cucurbitae, salivary gland, banding patterns, polytene maps.

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Zambetaki, Anna, Nicole Pasteur und Penelope Mavragani-Tsipidou. „Cytogenetic analysis of Malpighian tubule polytene chromosomes of Culex pipiens (Diptera: Culicidae)“. Genome 41, Nr. 6 (01.12.1998): 751–55. http://dx.doi.org/10.1139/g98-090.

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A simple technique is described for obtaining well-spread and readable Malpighian tubule polytene nuclei of Culex pipiens on a routine basis. Detailed polytene chromosome maps are presented with a description of the most prominent landmarks of each chromosome, the regions with asynapsis and the most frequent weak points identified in the polytene arms. Usable Malpighian tubule polytene chromosomes should facilitate molecular cytogenetic, genetic, and potentially biosystematic studies on this medically important global vector of viral inducing encephalitis.Key words: Culex pipiens, polytene chromosomes, Malpighian tubules, banding pattern, photomap.

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Henry, Willie, Subrata Kumar Dey, Rakesh Varma, Sachin Thapa und William S. Procunier. „Polytene chromosomes of an Indian Himalayan black fly Simulium (Nevermannia) praelargum (Diptera: Simuliidae)“. Current Zoology 56, Nr. 4 (01.08.2010): 437–44. http://dx.doi.org/10.1093/czoolo/56.4.437.

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Abstract High quality polytene chromosome maps (n=3) of a Himalayan Simuliid Simulium praelargum Datta, 1973 are presented and represent the first cytological description of a taxon found in the feuerborni group, subgenus Nevermannia. Polytene chromosomes one (I) and two (II) are metacentric, chromosome three (III) is submetacentric with the length of each chromosome occupying 37.25 %, 31.36 % and 31.34 % of the total complement length, respectively. Typical simuliid diagnostic intergeneric chromosomal markers are found within the polytene complement of this species. The nucleolar organizer (N.O.) is found at the base of the short arm of chromosome one (IS), the Ring of Balbiani (R.B.), double bubble (D.B.) and triad occur in the short arm of chromosome two (IIS), the Parabalbiani Ring (P.B.) and grey band (gb) occur in the long arm of chromosome two (IIL) and the Blister (BL) and Capsule (Ca) occur in the short arm of chromosome three (IIIS).Terminal bands at the end of IIIS are heterochromatinized and present atypically with respect to other simuliid fauna. Populations studied so far are unique among the Simuliidae in that they exhibit chromosome structural monomorphism. These high resolution polytene chromosome maps will form the basis for future cytological characterization and phylogenetic comparisons amongst members of the feuerborni group.

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Dissertationen zum Thema "Polytene chromosome"

Gan, Miao. „Analysis of Chriz involved in Drosophila polytene chromosome structuring and binding“. Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/16000.

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Polytäne Chromosomen von Drosophila sind in eine Abfolge von Banden und Interbanden unterschiedlichen Kompaktionsgrades gegliedert. Das Protein Z4 ist notwendig, um dieses Muster aufrecht zu erhalten (Eggert et al., 2004). Durch Koimmunpräzipitation mit Z4 wurde in unserer Arbeitsgruppe ein Chromodomänen Protein identifiziert, das von uns als Chriz bezeichnet wurde (Gortchakov et al., 2005). In meiner Arbeit testete ich die Interaktion zwischen den vollständigen Proteinen Chriz und Z4. Ich konnte dabei zeigen, dass beide Proteine in vivo direkt miteinander interagieren. Die kartierten Interaktionsdomänen am N-Terminus von Z4 und am C-Terminus von Chriz sind hinreichend für die wechselseitige Interaktion beider Proteine. Chriz ist wie Z4 in vielen Interbanden polytäner Interphasechromosomen gebunden. Die überexpression verschiedener Domänen von Chriz zeigte, dass sowohl der N- als auch der C-Terminus von Chriz für die Interbandenbindung von Chriz ausreichend sind. Der Chriz C-Terminus ist dar Über hinaus notwendig, um das überleben von Tieren mit einer Chriz Null Mutation bis in das larvale Stadium zu gewährleisten. Tiere mit induziertem Chriz RNAi knock down zeigten eine verringerte DNA Kondensation polytäner Chromosomen. Die Ähnlichkeit des chromosomalen Phänotyps von Z4 und Chriz Mutationen legt nahe, dass beide Proteine in einem gemeinsamen Komplex in Interbanden vorkommen. Unter Ausnutzung von Chriz RNAi bzw. Z4 RNAi konnte ich zeigen, dass die chromosomale Bindung von Z4 von Chriz abhängt. Weiterhin sind die Proteinkinase Jil-1 und an Serin 10 phosphoryliertes H3 (H3pS10), beides Marker für dekondensiertes Chromatin, in Chriz RNAi Tieren verringert. Aus meinen Daten schliesse ich, dass Chriz/Z4/Jil-1 in einem gemeinsamen Komplex an Interbanden gebunden sind. Chriz ist dabei fundamental wichtig für die zielgerichtete Bindung und Stabilität des Komplexes. Der Komplex selbst ist erforderlich, um die lokale Chromatinstruktur aufrecht zu erthalten.
Drosophila polytene chromosomes are compacted into a series of bands and interbands. Z4 is a protein to keep this pattern, since Z4 mutant larvae show a decompaction of chromosomes and a loss of banding pattern (Eggert et al., 2004). By coimmuno-precipitation, we identified a chromodomain protein, which we named Chriz, for chromodomain protein interacting with Z4 (Gortchakov et al., 2005). In my PhD thesis, I tested the interactions between the full length proteins and different fragments of Chriz and Z4 which showed that Chriz could directly interact with Z4 in vivo. The interaction domains were mapped and it was determined that the N terminus of Z4 and the C terminus of Chriz are sufficient for mutual interaction. GST pull down confirmed these data and more precisely localized the interaction domains. Chriz, like Z4, is present in many interbands of interphase polytene chromosomes. The overexpression of different domains of Chriz demonstrated that both the N and C terminus are sufficient for targeting of Chriz to interbands. The C terminus was shown to be sufficient for rescue of Chriz null mutations into larva stage. Chriz full length proteins, with site directed mutations within the chromodomain, could still partially rescue the null mutant. Chriz RNAi knock down resulted in a loss of structure of polytene chromosome. The similar chromosomal phenotype of Z4 and Chriz indicate that they cooperate in the formation of chromosomal structure. Using the Chriz RNAi, I showed that Z4 chromosomal binding is dependent on Chriz. However, by a similar assay I showed that Chriz binding did not depend on Z4. Finally, the decondensed interphase chromatin marker Jil-1, a H3S10 histone kinase, and H3pS10 are decreased in Chriz RNAi line. From these data, I conclude that Chriz/Z4/Jil-1 form an interband binding complex. Chriz is the fundamental factor for the chromosomal targeting and stabilitation of the complex that is required to maintain locally chromatin structure.

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Hartl, Tom A. „CONDENSIN II CHROMOSOME INDIVIDUALIZATION IS NECESSARY FOR MEIOTIC SEGREGATION AND ANTAGONIZES INTERPHASE CHROMOSOME ALIGNMENT“. Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195995.

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Maintenance of an intact genome and proper regulation of the genes within are crucial aspects for life. The work of this dissertation has implicated the Drosophila condensin II complex in both processes. Condensin II's ability to reconfigure chromosomes into spatially separated and discrete units is necessary to ensure proper meiotic segregation. When this "individualization" activity fails in a condensin II mutant, chromosomes remain entangled, and either cosegregate or become lost during cell division. This leads to the creation of aneuploid sperm. We have also implicated condensin II as a factor necessary to individualize interphase somatic chromosomes from one another. This is relevant in Drosophila because the association of homologous chromosomes is thought to facilitate gene regulation activity in trans. We speculate that condensin II individualization spatially distances aligned chromosomes from one another and prevents this trans-communication between allelic loci. This is supported first by an increase of homologous chromosome pairing in a condensin II mutant background. Secondly, loss of condensin II leads to elevated production from alleles that are known to depend on pairing for transcriptional activation. These meiotic and interphase condensin II roles support its necessity to Drosophila genome integrity and transcriptional regulation. Given the conservation of condensin from bacteria to humans, it is likely that equivalent or related roles exist in a variety of species.

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Thapa, Sachin. „Diversity of Simulium (Diptera: Simuliidae) from Darjeeling Hills based on Chromosomal study“. Thesis, University of North Bengal, 2017. http://hdl.handle.net/123456789/2781.

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Zielke, Thomas. „Strukturelle und funktionelle Analyse von chromosomalen Domänen mit Hilfe sequenz-spezifischer Rekombination in Drosophila“. Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17232.

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Polytäne Riesenchromosomen von Drosophila melanogaster bieten ein ideales Modellsystem für die Untersuchung der Mechanismen zur strukturellen Bildung chromosomaler Domänen. Über Manipulation und Rekonstruktion des chromosomalen Bandenmusters polytäner Chromosomen können artifiziell kondensierte als auch dekondensierte Domänen etabliert werden. Diese Eigenschaft habe ich in meiner Arbeit genutzt für die Etablierung eines experimentellen Systems zur Analyse der strukturellen Vorraussetzungen zur Bildung offener Chromatindomänen. Dafür wurde eine transgene kondensierte Chromatindomäne ektopisch innerhalb offenen Chromatins generiert. Diese kondensierte „Modellbande“ bietet einen definierten genetischen Hintergrund für die gezielte Insertion von DNA-Sequenzen unter Ausschluss variabler Positionseffekte und ermöglicht dadurch eine vergleichende Analyse dieser Sequenzen auf ihr Vermögen offenes Chromatin zu bilden. Zu diesem Zweck wurde über Sequenz-spezifische Rekombination die 61C7/8 Interbandensequenz gezielt in die „Modellbande“ eingefügt. Die zytogenetische Untersuchung dieser Insertion zeigt, dass infolge der Insertion offenes Chromatin gebildet wird, was in einer Aufsplittung der kondensierten „Modellbande“ resultiert. Molekulare Analysen weisen darauf hin, dass auch die epigenetischen Charakteristika wie z.B. die Rekrutierung typischer Proteine oder transkriptionelle Eigenschaften zur endogenen Domäne immitiert werden. Über Deletionsanalysen konnte von mir die essentielle DNA-Sequenz zur Bildung offenen Chromatins auf ein ~490bp großes Fragment im proximalen Bereich der 61C7/8 Sequenz kartiert werden. Dieses Fragment überlappt mit Bindungsstellen spezifischer Proteine, welche dafür bekannt sind eine Rolle in der chromosomalen Domänenbildung zu spielen wie z.B. das Chromatin-Protein Chriz, die Histon-Kinase Jil1 oder das Insulator-Protein CP190. Desweiteren überlappt es mit einer Promoterregion, welche zwischen den Genen Rev1 und Med30 lokalisiert ist.
Polytene chromosomes of Drosophila melanogaster provides an ideal model-system for the analysis of the mechanisms needed for chromosomal domain formation. Condensed as well as decondensed chromosomal domains can be formed by manipulating and reconstructing the polytene banding pattern. This possibility i ha-ve used for the establishment of an experimental system to study the structural requirements for open chromatin formation. Therefor i have generated a condensed chromatin domain at ectopic positions. This condensed „model“ domain provides a defined genetic context for the targeted insertion of sequences of interest, excluding any variable position effects. This allows comarative analysis of different sequences in order to identify the structural requirements for open chromatin formation. For this purpose the 61C7/8 interband sequence was targetly integrated into the condensed „model“ domain by site-specific recombination. Thereby i could show that the 61C7/8 interband sequence maintains the capacity to form open chromatin cognizable by the splitting of the condensed „model“ domain. Furthermore the newly formed open chromatin domain also keeps epigenetic characteristica like transcriptional activity or the recruitment of typical proteins. By deletion analysis, i have mapped the essential region needed for open chromatin formation to a ~490bp fragment located in the proximal part of the 61C7/8 interband sequence. This fragment overlaps binding sites for characteristic proteins known to be involved in chromosomal domain formation like the chromatin protein Chriz, the histone kinase Jil1 or the insulator protein CP190. Furthermore the fragment overlaps a promoter region that locates between the Rev1 and Med30 genes.

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Gilligan, Deirdre. „Molecular and cytological studies of the BR6 gene in Chironomus tentans polytene chromosomes /“. [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10879.

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George, Phillip John-Paul. „The organization and evolution of heterochromatin in the Anopheles gambiae complex“. Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/56663.

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The Anopheles gambiae complex is comprised of the most important vectors of malaria in Sub-Saharan Africa. Most current control methods involve the use of chemicals that help to limit potential contact with these mosquitoes. However, these control methods still have risks that include insect resistance, environmental toxicity, human health, as well as animal health. In order to develop new strategies that either produce novel targeted insecticides or transgenic mosquitoes that can replace current mosquito populations, it is important to acquire as much biological information about the vector as possible. The reduction in cost and speed of high-throughput sequencing has brought forth many new sequenced genomes that can provide a wealth of information about individual populations as well as their respective evolutionary histories. However, in order to fully understand a genome, these sequences must be assembled properly. One of the largest challenges toward fully assembling a genome is the abundance of repetitive sequences. These sequences, typically part of gene poor regions known as heterochromatin, are generally left as unassembled scaffolds that are neglected in many genomic studies. Heterochromatin is a biologically important chromatin state that has roles in gene regulation and genome stability. Exclusion of these chromatin domains from experimental assays can provide an incomplete picture in regards to organismal biology. A lack of information regarding heterochromatin, even in An. gambiae, necessitates further understanding and characterization of this chromatin type that can provide valuable information about the mosquito's biology. Heterochromatin is organized differently amongst different species. Some species with compact genomes, like Drosophila melanogaster, exhibit rigid organization of heterochromatin, with repetitive elements being confined to peri-centromeric and sub-telomeric regions of the chromosome. Larger genomes such as Aedes aegypti, have a much less structured heterochromatin pattern, with repetitive elements being dispersed across the genome. However, An. gambiae's genome is more intermediate in size as well as transposable element content. These factors may have an impact in controlling how heterochromatin is organized within the An. gambiae genome. Does An. gambiae compensate for the increased genome size by expanding past the peri-centromeric heterochromatin into new intercalary compartments? In An. gambiae, heterochromatin had yet to be identified separately from euchromatin. Morphologically, some regions of An. gambiae chromosomes exhibited characteristics similar to transcriptionally active puffs or peri-centromeric heterochromatin. We characterize these regions, as well as the rest of the genomic landscape, by using morphological and genetic features to identify various chromatin types. Peri-centromeric heterochromatin and new regions of intercalary heterochromatin were identified. Genomic coordinates representing the transition from euchromatin to heterochromatin were also identified. By finding these heterochromatin-euchromatin boundaries, various genetic features could be assigned to either heterochromatin or euchromatin. Critical genes associated with heterochromatin formation and basic genomic functions were identified. These data help to better understand features that are associated with the different environments created by chromatin compaction. This study also looks at the Piwi-interacting RNA (piRNA) pathway and its role in An. gambiae. The piRNA pathway is associated with transposable element (TE) suppression in many species, where clusters of vestigial TEs provide some of the RNA necessary for the pathway to function. These clusters are primarily associated with heterochromatin in Drosophila melanogaster. We identify piRNA clusters in An. gambiae and see a similar shift from primarily peri-centromeric compartmentalization toward the presence of intercalary regions located within the euchromatin. Transposable elements are maintained in secondary heterochromatin regions that exhibit similar morphology and features to peri-centromeric heterochromatin. The piRNA pathway also has implications in gene regulation, germline development, and anti-viral immunity. Three candidate genes associated with spermatogenesis and embryogenesis have been identified. These genes showed piRNA enrichment, and upon further analysis show up-regulation after a blood meal is taken. These genes could potentially prove useful in vector control as targets of transgenic experiments. Heterochromatin is an important, yet neglected aspect of the genome. These studies attempt to provide data to stimulate the study of heterochromatin through characterization of heterochromatin-related genomic features.
Ph. D.

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Roy, Choudhury Subhendu. „Visualization of Exon Junction Complex (EJC) and related factors at transcription sites of Drosophila polytene chromosomes“. Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6560/.

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It was long believed that cytoplasmic events like translation and mRNA degradation are not linked to nuclear events such as pre-mRNA splicing. However, current observation indicates that nucleus/cytoplasm communication is mediated by the exon junction complex (EJC), a multiprotein complex deposited during splicing in the nucleus. The consensus is that the EJC is deposited exclusively on spliced mRNA, 20-24 nucleotides upstream of the exon-exon junction. Splicing appears to deposit the EJC similarly in \(Drosophila\) \(melanogaster\), yet it has also been reported that, in contrast to mammalian cells, the EJC might be required for splicing, suggestive an earlier association with pre-mRNA. My PhD project aimed to visualize the assembly of the EJC on nascent RNA at polytene chromosome transcription sites. The main conclusion of these studies is that, contrary to current predictions, EJC components are recruited at transcription sites corresponding to both intron-containing and intron-less genes. A similar conclusion was reached in \(Drosophila\) S2 cells, where chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) data indicates, the core EJC protein Y14 associates to transcription sites independently of the gene having introns. Additionally, in a parallel projects my data also suggest that ribosomal proteins and UPF1 also associate with Pol II transcription sites.

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Brehm, António. „Phylogénie de neuf espèces de Drosophila du groupe obscura d'après les homologies de segments des chromosomes polytènes“. Lyon 1, 1990. http://www.theses.fr/1990LYO10124.

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Dans ce travail nous presentons une esquisse de l'arbre phylogenetique de neuf especes (d. Subobscura, madeirensis, guanche, obscura, ambigua, tristis subsilvestris, kitumensis, microlabis) du groupe obscura du genre drodophila (sous genre sophophora) etabli a partir des homologies de segments des chromosomes polytenes de ces especes. Ces homologies sont basees sur les similitudes des sequences des bandes qui caracterisent les chromosomes des especes. Deux approches differentes sont utilisees: 1) quand l'homologie de tous les segments ne peut pas etre etablie, nous basons nos conclusions sur des donnees qualitatives, qui permettent une stricte derivation des relations phylogenetiques grace a l'application de la methode dite des inversions imbriquees de sturtevant et dobzhansky (1936); 2) lorsque l'homologie des segments concerne la totalite de la longueur du chromosome, il est possible d'estimer le nombre minimum d'inversions requis pour la transformation d'une sequence dans une autre. Ces nombres jouent le role de distances grace auxquelles un arbre est construit en appliquant un algorithme approprie. Une recherche de sequences ancestrales hypothetiques communes a plusieurs voies de transition entre especes est a la base d'une autre methode de construction d'arbre phylogenetique

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Poisot, Emilie. „Recrutement des complexes des groupes Polycomb et trithorax sur la chromatine : Dissection fonctionnelle des complexes liant les séquences d(GA)n des éléments de mémoire épigénétique“. Versailles-St Quentin en Yvelines, 2010. http://www.theses.fr/2010VERS0022.

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Au moins trois mécanismes sont connus pour influer sur le maintien des profils d’expression des gènes: l’état chromatinien, les modifications épigénétiques liées aux protéines du groupe Polycomb (PcG) et Trithorax (trxG), et les ARN non codants (ARNnc). Les gènes du PcG et trxG maintiennent l’identité au cours du temps par des processus épigénétiques figeant un état transcriptionnel déterminé qui constitue la « mémoire cellulaire ». Les trois protéines Batman (BAN), Trithorax-like (GAF) et Pipsqueak (PSQ) font partie de complexes de mémoire cellulaire qui lient l’ADN. Le premier objectif de ma thèse était d’affiner la description des complexes contenant BAN, GAF et PSQ fixés sur leurs cibles. J’ai montré l’existence de plusieurs complexes, indiquant qu’il existe une combinatoire dans ces complexes en fonction de la cible. En réalisant une extinction ciblée de l’une ou l’autre de ces protéines, j’ai étudié leur hiérarchie de recrutement. L’élargissement de cette étude à d’autres protéines PcG et trxG a permis ensuite de modéliser le recrutement des différents complexes de mémoire. J’ai parallèlement étudié le lien existant entre la formation de l’hétérochromatine et les ARN non codants (ARNnc). A l’aide de mutants affectant des voies de production d’ARNnc, j’ai montré qu’ils participent à la localisation d’HP1 sur chromosomes polytènes et donc à la formation de hétérochromatine. L’ensemble de ces études a permis de caractériser la complexité des relations entre BAN, GAF et PSQ et de définir leur importance respective dans le recrutement différentiel de complexes PcG ou trxG, mais aussi de contribuer à établir le lien entre les ARNnc et la formation de l’hétérochromatine
At least three important mechanisms are known to maintain gene expression patterns: the chromatine state, the epigenetic modifications due to the Polycomb ( PcG) and Trithorax ( TrxG ) groups proteins, and non coding RNAs (ncRNAs). The PcG and trxG genes maintain cell identity through epigenetic modifications of chromatin, thereby maintaining a predefined transcriptional state that establishes "cell memory". Three proteins, i. E. Batman (BAN), Trithorax-like (GAF) and Pipsqueak (PSQ) are components of a DNA-binding cell memory complex. The first goal of my thesis was to refine the description of complexes containing BAN, GAF and PSQ bound to their targets. I showed the existence of several complexes, suggesting a combinatory composition of these complexes depending on the target. Using dsRNA-driven extinction of each of the three proteins, I determined the hierarchy of their recruitment. The extension of this approach to other PcG and trxG proteins lead us to propose a new model for the recruitment of several of the memory complexes. I also studied the link between heterochromatin formation and ncRNAs. By using mutants affecting pathways of ncRNAs production, I showed that they participate in the localization of the heterochromatin protein HP1 on polytene chromosomes and thus in the formation of heterochromatin. All these studies allowed us to characterize the complexity of relations between BAN, GAF and PSQ and to define their respective contribution in the differential recruitment of PcG or TrxG complexes, but also to contribute to establishing the link between the ncRNAs and heterochromatin

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Andrade, Alexandre de. „Identificação, caracterização e estudo da expressão dos genes hsc70 e hsp83 em Rhynchosciara americana“. Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-29122006-171314/.

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Com a idéia de identificar proteínas envolvidas no processo de enovelamento das proteínas sintetizadas na glândula salivar de Rhynchosciara americana, no início deste projeto adotou-se como estratégia o seqüenciamento de uma biblioteca de cDNA. Esta biblioteca foi construída utilizando-se glândulas salivares de Rhynchosciara americana do período de seu desenvolvimento onde tem início a síntese de seu casulo. Mensagens de proteínas envolvidas no processo de enovelamento, transporte e proteólise foram isoladas, alguns exemplos são hsc70, hsp83, hip, hop, dnaJ, trap1 e prolil isomerase, sec61α/β, sec23, peptidase de sinal, rab7, partícula reconhecedora de sinal (srp), enzima conjugadora de ubiquitina e complexo regulatório proteassomo 26, cop 1 e ubiquitina ligase. A identificação destes genes permitiu o isolamento de clones genômicos através de triagem em banco de fagos e caracterização dos genes hsc70 e hsp83 para verificação de sua organização em Rhynchosciara americana. A expressão dos seus respectivos mRNAs foi avaliada em vários períodos do último estágio larval. A localização por hibridização in situ mostrou que estes genes estão localizados em regiões dos cromossomos politênicos próximas a dois pufes de DNA, C3 e C8. O estudo dos níveis de expressão das proteínas codificadas pelos genes hsc70 e hsp83 mostrou a diferença de comportamento destes genes sob condições de estresse térmico e que a expressão destas proteínas deve ser regulada pelo período de desenvolvimento das larvas de Rhynchosciara americana. Quando evidenciada por imunofluorescência a proteína Hsc70 mostra localização predominantemente no citoplasma.
With the idea of identify some of these proteins involved in the folding process of the proteins synthesized on the Rhynchosciara salivary gland, this project started adopting the shotgun cDNA sequencing strategy. This cDNA library was constructed utilizing salivary glands of Rhynchosciara americana at a developmental period where the cocoon construction begins. Messengers of important proteins involved in the folding, transport and proteolysis process were isolated, some examples are hsc70, hsp83, hip, hop, sec61 α/β, sec23, signal peptidase, rab7, signal recognition particle (srp), ubiquitin conjugating enzyme e 26 proteasome regulatory complex, cop 1 and ubiquitin ligase. Identification of these genes allowed the screening of genomic clones from a phage library; hsc70 and hsp83 characterization was carried out to verify the arrangement of these genes on genome of Rhynchosciara americana. The study of these genes will contribute with phylogenetic information about the specie. The mRNA expression of these genes was analyzed during several periods of the last larval developmental stage. In situ localization showed that these genes are located in polytene chromosomes regions near two DNAs puffs, C3 and C8. The expression levels of the proteins codified by genes hsc70 and hsp83 showed different behaviors of these genes under heat stress conditions and mainly, that the regulation of the proteins Hsc70 and Hsp83 can be related to the period of development of the larvae of Rhynchosciara americana. When revealed by immunofluorescence, Hsc70 protein shows localization predominantly on the cytoplasm.

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Bücher zum Thema "Polytene chromosome"

Polytene chromosomes in genetic research. Chichester: E. Horwood, 1988.

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Sorsa, Veikko. Polytene chromosomes in genetic research. Chichester [England]: E. Horwood, 1988.

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Brodskii, V. I. A. Genome multiplication in growth and development: Biology of polyploid and polytene cells. Cambridge: Cambridge University Press, 1985.

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V, Uryvaeva I., und Brodskiĭ, V. I͡A. Kletochnai͡a poliploidii͡a., Hrsg. Genome multiplication in growth and development: Biology of polyploid and polytene cells. Cambridge [Cambridgeshire]: Cambridge University Press, 1985.

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Polytene Chromo Genetic Res. Prentice Hall, 1988.

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Kasimer, Dahlia Arielle. Localization of general transcription factors and RNA polymerase II on Drosophila polytene chromosomes. 2004.

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Brodsky, V. Ya, und I. V. Uryuvaeva. Genome Multiplication in Growth and Development: Biology of Polyploid and Polytene Cells (Developmental and Cell Biology Series). Cambridge University Press, 1985.

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Buchteile zum Thema "Polytene chromosome"

Gooch, Jan W. „Polytene Chromosome“. In Encyclopedic Dictionary of Polymers, 916. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_14540.

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Guerra, Marcelo. „Fluorescent in situ hybridization in plant polytene chromosomes“. In Chromosome Painting, 133–38. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0330-8_13.

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della Torre, Alessandra. „Polytene chromosome preparation from anopheline mosquitoes“. In The Molecular Biology of Insect Disease Vectors, 329–36. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-1535-0_28.

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Elgin, S. C. R., S. A. Amero, J. C. Eissenberg, G. Fleischmann, D. S. Gilmour und T. C. James. „Distribution Patterns of Nonhistone Chromosomal Proteins on Polytene Chromosomes: Functional Correlations“. In Chromosome Structure and Function, 145–56. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-1037-2_6.

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Frank, J. Howard, J. Howard Frank, Michael C. Thomas, Allan A. Yousten, F. William Howard, Robin M. Giblin-davis, John B. Heppner et al. „Polytene Chromosomes“. In Encyclopedia of Entomology, 2997–98. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6359-6_3064.

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Korge, G. „Polytene Chromosomes“. In Results and Problems in Cell Differentiation, 27–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-540-47783-9_3.

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Laird, C., M. Hammond und M. Lamb. „Polytene chromosomes of Drosophila“. In Chromosomes Today, 40–47. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-010-9166-4_5.

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Kraemer, Christiane, und Erwin R. Schmidt. „Mapping of Polytene Chromosomes“. In Nonradioactive Analysis of Biomolecules, 516–23. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-642-57206-7_46.

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Hofmann, A., und G. Korge. „Polytene Chromosomes in Mutagenesis“. In Advances in Mutagenesis Research, 115–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-77466-9_7.

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Kumar, Vasantha, Anthony J. Cornel und Odette Mukabayire. „In situ hybridization to Anopheles polytene chromosomes“. In The Molecular Biology of Insect Disease Vectors, 337–45. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-1535-0_29.

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Konferenzberichte zum Thema "Polytene chromosome"

Gammanpila, H. W., und K. R. Manjula. „Exploring the Influence of Intermittent Heat Exposure on Spontaneous Mutations in Drosophila melanogaster: Assessing the Role of Vitamin C in Mitigating Heat Stress and Examining Inheritance Patterns of Induced Mutations“. In SLIIT International Conference on Advancements in Sciences and Humanities 2023. Faculty of Humanities and Sciences, SLIIT, 2023. http://dx.doi.org/10.54389/thuh5711.

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Climate change poses a significant threat to the well-being of organisms. It has a detrimental impact on the survival of smaller organisms in response to climatic shifts, posing a substantial danger to biodiversity, which is already under stress due to habitat loss, emerging invasive species, and diseases. This study aimed to assess the influence of fluctuating temperatures on the physiology and behavior of Drosophila melanogaster, as well as to investigate whether such temperature fluctuations have any effect on phenotypic expression through potential spontaneous mutations. Genotypic changes were examined by observing cytological alterations in the salivary gland chromosomes. Drosophila melanogaster were exposed to intermittent heat conditions for a period of two weeks. The experimental setup was divided into four groups: a control group maintained at room temperature (25±2°C), a group at room temperature supplemented with vitamin C, a group exposed to heat at 38±2°C, and a group exposed to 38±2°C with vitamin C supplementation. Revival of the flies was noticeably better in the vitamin C supplemented group. These flies exhibited a higher revival rate even after exposure to the heat stress. Salivary gland chromosome analysis provided intriguing insights. More balbiani rings were observed, indicating elevated mRNA production during the heat exposure. Furthermore, an increase in the number of puffs in polytene chromosomes was noted, suggesting an overall increase in mRNA production in the heat-exposed flies. Additionally, the evaluation of wing mutants yielded important findings. It became evident that these mutations were not related to vestigial or curly wing traits. Instead, they indicated that heat exposure was damaging wing formation, resulting in abnormal wing patterns. These results suggest a substantial impact of temperature fluctuations on insect behavior, which can even lead to the induction of mutations. Generational studies further indicate that these mutations can be inherited.

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Salleh, Syafinaz, und Ahmad Abas Kutty. „Chironomus group classification according to the mapping of polytene chromosomes“. In THE 2013 UKM FST POSTGRADUATE COLLOQUIUM: Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2013 Postgraduate Colloquium. AIP Publishing LLC, 2013. http://dx.doi.org/10.1063/1.4858722.

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Brill, Gregory E., Oksana R. Apina, Svetlana I. Belyanina und Nadezda P. Panina. „Effect of He-Ne laser radiation on polytene chromosomes of Chironomus“. In Europto Biomedical Optics '93, herausgegeben von Kazuhiko Atsumi, Cornelius Borst, Frank W. Cross, Herbert J. Geschwind, Dieter Jocham, Jan Kvasnicka, Hans H. Scherer, Mario A. Trelles und Eberhard Unsoeld. SPIE, 1994. http://dx.doi.org/10.1117/12.169140.

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Yesmin, Farzana, Md Uddin und Md Hasanuzzaman. „Structural Maps of the Polytene Chromosomes of the Fruit Flies <em>Bactrocera zonata</em> and <em>Zeugodacus tau</em> (Diptera: Tephritidae)“. In The 1st International Electronic Conference on Entomology. Basel, Switzerland: MDPI, 2021. http://dx.doi.org/10.3390/iece-10528.

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Berichte der Organisationen zum Thema "Polytene chromosome"

Nordeen, Steven. Exploiting Polytene Chromosomes to Identify Transcription CoFactors and Complexes Recruited to an Estrogen Responsive Promoter in Vivo. Fort Belvoir, VA: Defense Technical Information Center, Juni 2003. http://dx.doi.org/10.21236/ada417949.

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