Dissertationen zum Thema „Ribosomal maturation“
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Nord, Stefan. „The importance of maturation factors in 30S ribosomal subunit assembly“. Doctoral thesis, Umeå universitet, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-35890.
Der volle Inhalt der QuelleMonteringen av ribosomen är en komplex process som måste vara effektiv för cellen skall kunna växa så fort som möjligt. Det är visat sedan tidigare att ribosomens två subenheter kan monteras ihop in vitro och sedan vara del av en ribosom som gungerar vid proteinsyntes, dock är den typen av rekonstrueringsreaktioner mycket ineffektiva i jämförelse med vad som krävs in vivo. Skillnaden mellan dessa två tillstånd är primärt in vivo-reaktionens närvaro av hjälpproteiner. Hjälpproteinerna assisterar monteringen av ribosomens subenheter men är själva inte en del av den färdiga ribosomen. Inom denna klass av proteiner återfinns proteiner som t.ex. processerar ribosomalt RNA och proteiner som modifierar ribosomalt RNA och ribosomala protein. En klass av hjälpproteiner, mognadsfaktorerna, har varit svåra att klassificera på grund av strukturella olikheter och en brist på funktionella likheter. En del i detta avhandlingsarbete var karaktäriseringen av den tidigare okända mognadsfaktorn RimP, tidigare kallad YhbC eller P15A. En deletion av rimP hade störst påverkan på tillväxthastigheten vid 44°C, men effekter kunde även ses vid 30°C och 37°C. En analys av den ribosomala statusen visade på en minskning av ribosomer aktiva i translation och en motsvarande ökning av fria 50S- och 30S-subenheter. Den oproportionerligt höga ökningen av fria 50S-subenheter, i relation till 30S-subenheter, indikerade att något var fel i monteringen av 30S-subenheten. RimP-proteinet återfanns lokaliserat till fria 30S-subenheter, och en ökning av omoget 16S ribosomalt RNA i en stam som saknar RimP stödjer dess roll i monteringen av 30S-subenheten. Rekonstrueringsexperiment In vitro har gett många värdefulla ledtrådar till hur 30S-subenheten monteras ihop. Genom att använda en nyligen utvecklad metod kunde vi undersöka hur mognadsfaktorerna Era, RimM och RimP påverkade monteringen av ribosomens 30S subenhet in vitro. Era ökade inkorporeringshastigheten av många av de ribosomala proteiner som inkorporeras sent i monteringen av 30S, medans RimM och RimP uppvisade mer specifika effekter. RimM ökade inkorporeringshastigheten för de ribosomala proteinerna S19 och S9, men dessutom inhiberade RimM inkorporeringen av de ribosomala proteinerna S13 och S12. RimP uppvisade den tydligaste effekten av de undersökta proteinerna genom att kraftigt öka 8 inkorporeringshastigheten för det ribosomala proteinet S12, och ökade även inkorporeringshastigheten för det ribosomala proteinet S5. En jämförelse av de två mognadsfaktorerna RbfA och RimP visade på strukturella likheter mellan RimP:s N-terminala domän och den enda domänen hos RbfA. RbfA är ett 15 kDa protein som upptäcktes som en hög-kopiesupressor av en dominant C23U-mutation i 16S ribosomalt RNA som leder till köld-känslighet hos E. coli. Ett antal kromosomala supressormutationer som ökade tillväxthastigheten för en mutant som saknar RbfA isolerades och de fem starkaste av dessa lokaliserades till rpsE genen som kodar för det ribosomala proteinet S5. Mutationerna gav upphov till aminosyra utbyten i tre positioner i S5: G87A, G87S, G91A, A127T och A127V. Förändringarna i S5 förbättrade translationen och processningen av 16S ribosomalt RNA i mutantensom saknar RbfA. Dessutom förbättrade mutationerna tillväxthastigheten hos C23U-mutanten vid 30, 37 och 44°C.
Trinquier, Aude. „Coupling between transfer RNA maturation and ribosomal RNA processing in Bacillus subtilis“. Thesis, Université de Paris (2019-....), 2019. http://www.theses.fr/2019UNIP7066.
Der volle Inhalt der QuelleCellular protein synthesis both requires functional ribosomes and mature transfer RNAs (tRNAs) as adapter molecules. The ribosomes are large essential ribonucleoprotein complexes whose biogenesis accounts for most of cellular transcription and consumes a major portion of the cell’s energy. Ribosome biogenesis is therefore tightly adjusted to the cellular needs and actively surveilled to rapidly degrade defective particles that could interfere with translation. Interestingly, tRNAs and ribosomal RNAs (rRNAs) are both transcribed from longer primary transcripts and universally require processing to become functional for translation. In this thesis, I have characterized a coupling mechanism between tRNA processing and ribosome biogenesis in the Gram-positive model organism Bacillus subtilis. Accumulation of immature tRNAs during tRNA maturase depletion, specifically abolishes 16S rRNA 3’ processing by the endonuclease YqfG/YbeY, the last step in small ribosomal subunit formation. We showed that this maturation deficiency resulted from a late small subunit (30S) assembly defect coinciding with changes in expression of several key 30S assembly cofactors, mediated by both transcriptional and post-transcriptional effects. Interestingly, our results indicate that accumulation of immature tRNAs is sensed by the stringent factor RelA and triggers (p)ppGpp production. We showed that (p)ppGpp synthesis and the accompanying decrease in GTP levels inhibits 16S rRNA 3’ processing, most likely by affecting GTPases involved in ribosome assembly. The inhibition of 16S rRNA 3’ processing is thought to further lead to degradation of partially assembled particles by RNase R. Thus, we propose a model where RelA senses temporary slow-downs in tRNA maturation and this leads to an appropriate readjustment of ribosome biogenesis. This coupling mechanism would maintain the physiological balance between tRNAs and rRNAs, the two major components of the translation machinery
Akhtar, Y. „Studies on the maturation pathway of ribosomal precursor RNA : Analysis of Xenopus ribosomal RNA synthesised by transcription in vitro“. Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382054.
Der volle Inhalt der QuelleDurovic, Peter Vincent. „Characterisation of a novel pathway for ribosomal RNA maturation in Sulfolobus acidocaldarius“. Thesis, University of British Columbia, 1993. http://hdl.handle.net/2429/41498.
Der volle Inhalt der QuelleMedicine, Faculty of
Medical Genetics, Department of
Graduate
Intine, Robert V. A. „Structural features of the 5' ETS in Schizosaccharomyces pombe essential for ribosomal RNA maturation“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0006/NQ40374.pdf.
Der volle Inhalt der QuelleBraun, Christina [Verfasser], und Jorge [Akademischer Betreuer] Perez-Fernandez. „Functional characterization of Pol5 in the maturation of both ribosomal subunits / Christina Braun ; Betreuer: Jorge Perez-Fernandez“. Regensburg : Universitätsbibliothek Regensburg, 2020. http://d-nb.info/1220080578/34.
Der volle Inhalt der QuelleTeubl, Fabian [Verfasser], und Joachim [Akademischer Betreuer] Griesenbeck. „Structural and Functional Studies on the Role of Noc3p for Large Ribosomal Subunit Maturation in Saccharomyces cerevisiae / Fabian Teubl ; Betreuer: Joachim Griesenbeck“. Regensburg : Universitätsbibliothek Regensburg, 2020. http://d-nb.info/1223198138/34.
Der volle Inhalt der QuelleTAVERNITI, VALERIO. „RNA MATURATION/DEGRADATION IN MYCOBACTERIA: IN VIVO AND IN VITRO CHARACTERIZATION OF RNASE J AND RNASE E“. Doctoral thesis, Università degli Studi di Milano, 2011. http://hdl.handle.net/2434/151782.
Der volle Inhalt der QuelleDumont, Julien. „Contrôle des divisions asymétriques et de l'arrêt CSF dans l'ovocyte de souris : rôles de la GTPase Ran, de la Formine-2 et de p90rsk“. Paris 6, 2006. http://www.theses.fr/2006PA066357.
Der volle Inhalt der QuelleBertrand, Alexis. „Caractérisation fonctionnelle de mutations somatiques compensatrices d'elF6 dans le contexte du syndrome de Shwachman- Diamond“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL089.
Der volle Inhalt der QuelleShwachman Diamond syndrome (SDS) is a rare genetic ribosomopathy leading to impaired protein synthesis, which causes numerous symptoms including bone marrow failure and neutropenia that can evolve to myelodysplasia syndrome or acute myeloid leukaemia. Biallelic mutations in the SBDS gene are responsible of above 90% of the SDS cases and we recently identified biallelic EFL1 mutations as a novel cause of SDS. SBDS together with EFL1 remove the anti-association factor elF6 from the pre60S ribosomal subunit, allowing its interaction with the 40S subunit to form the mature ribosome 80S. Natural acquisition of somatic genetic events over time participâtes to age-related diseases and cancer development. However, in Mendelian diseases these events can, in rare case, counteract the deleterious effect of the germline mutation and provide a sélective advantage to the somatically modified cells, a phenomenon dubbed Somatic Genetic Rescue (SGR). We recently showed that several somatic genetic events affecting the expression or function of elF6 are frequently detected in blood clones from SDS patients but not in healthy individuals, suggesting a mechanism of SGR. While most of these somatic mutations induce elF6 destabilization or EIF6 haploinsufficiency, one récurrent mutation (N106S) did not affect the expression of elF6 but rather impact its ability to interact with the 60S subunit. In order to further investigate the functional conséquences of ElF6 haploinsufficiency and N106S mutation in a context of SDS, I introduced via CRISPR/Cas9 these mutations in immortalized fibroblastic cell line from SDS patients and control. These original cellular models hâve made it possible to détermine the impact of the N106S mutation on the localisation and function of elF6 and also to clarify the effects of these mutations on several aspects of cellular fitness, in particular ribosome biogenesis, translation rate and cell prolifération. Overall, the development of these cellular models has helped to characterise how the somatic N106S mutation and elF6 haploinsufficiency confer a sélective advantage in cells déficient in SBDS or EFL1
Carron, Coralie. „Maturation des pré-ribosomes humains et nucléologenèse post-mitotique“. Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1102/.
Der volle Inhalt der QuelleMostly studied in the yeast S. Cerevisiae, ribosome biogenesis is a ubiquitous process, which is still poorly described in mammals. Recent studies performed in these organisms have revealed new maturation steps in mammals. These differences between yeast and human pre-rRNA processing together with the increasing number of diseases linked to ribosome biogenesis defects have fueled interest for these mechanisms in pluricellular organisms, especially Human. The objective of this thesis was to better define the mechanism underlying assembly and maturation of the small subunit, the production of which is simpler than that of the large subunit. This study was focused in two human orthologs of yeast pre-ribosomal factors, Enp1p and Tsr1p, known to be required at distinct steps of 40S particle maturation, i. E. Early and nuclear step for Enp1p and late and cytoplasmic step for Tsr1p. Our results show that these two proteins have conserved functions in mammalian small subunit biogenesis compared to yeast. However, we also find differences in the coordination between the export and the maturation of the pre-40S particle, and we describe a new 18S rRNA processing intermediate in human cells, the 21S-C pre-rRNA. After depletion of bystin or ribosomal protein, we unexpectedly observed a defect in pre-nucleolar bodies resorption at the end of the mitosis. Pre-nucleolar bodies (PNBs) are transient structures, described as assembly platforms for nucleoli reformation. Our results show for the first time that ribosome maturation is reactivated in PNBs. This leads us to propose that the ordered and progressive resorption of PNBs at the unset of the G1 phase is directed by pre-rRNA processing. Interestingly, depletion of some ribosomal proteins involved in DBA prevents resorption of PNBs and delays progression through G1 phase, which raises the issue of the possible involvement of post-mitotic nuclear organization defects in pathophysiological mechanisms. These results highlight ribosome biogenesis specificities in mammals and define part of post-mitotic nucleologenesis mechanisms
Schillewaert, Stéphanie. „Etude de la maturation et de l'assemblage du ribosome eucaryote: caractérisation fonctionnelle de nouveaux facteurs trans-“. Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209826.
Der volle Inhalt der QuelleParmi ces facteurs de synthèse, nous avons caractérisé en détail, chez la levure et chez l’homme, la protéine Las1 impliquée dans la maturation des deux extrémités de l’ITS2, séquence qui sépare les ARNr 5.8S et 25S/28S. Chez la levure, en absence de la protéine Las1, les analyses de profils de polysomes révèlent un déficit de sous-unité 60S et l’apparition d’« halfmères ». Les techniques de purification d’affinité et de gradient de sédimentation nous indiquent que Las1 est associée aux pré-ribosomes 60S et qu’elle interagit avec de nombreux facteurs de synthèse de la petite, de la grande sous-unité ou des deux. De plus, Las1 copurifie avec des pré-ribosomes qui contiennent aussi les exoribonucléases 5’-3’ Rat1/Rai1 et Xrn1. Rai1 coordonne la maturation aux deux extrémités de l’ARNr 5.8S. Nous suggérons que Las1 appartient à un macrocomplexe connectant spatialement des sites de clivages éloignés sur la séquence primaire du pré-ARNr qui seraient rapprochés suite au reploiement de l’ITS2.
Un autre aspect de ce travail de thèse consiste en l’étude de l’assemblage des particules ribonucléoprotéiques et plus spécifiquement du pré-ribosome et des sous-unités ribosomiques eucaryotes. Nous avons utilisé la technique d’immunoprécipitation de chromatine (Ch-IP) pour caractériser l’assemblage d’une structure appelée le « SSU processome ». Celui-ci correspond à un pré-ribosome en formation ainsi que l’assemblage des protéines ribosomiques sur l’ARNr naissant.
Enfin, nous avons étudié le rôle d’une plateforme d’activation de méthyltransférases d’ARN et de protéines, la protéine Trm112 dans la ribogenèse. Nous avons montré que chez la levure, Trm112 est impliquée dans la synthèse du ribosome et dans la progression de la mitose. En absence de cette protéine, les pré-ARNr sont dégradés par un mécanisme de surveillance. Trm112 copurifie avec plusieurs facteurs de synthèse du ribosome dont la méthyltransférase Bud23, impliquée dans la modification post-transcriptionnelle de l’ARNr18S. Trm112 est requise pour cette méthylation et nous postulons que la protéine Bud23 est incapable de se lier aux pré-ribosomes en l’absence de Trm112.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Bordonné, Rémy. „Structure et expression de genes mitochondriaux de la levure saccharomyces cerevisiae : etude de la maturation des produits de transcription du dna mitochondrial“. Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13187.
Der volle Inhalt der QuelleSoudet, Julien. „Étude de la maturation cytoplasmique de la petite sous-unité ribosomique chez Saccharomyces cerevisiae“. Toulouse 3, 2009. http://thesesups.ups-tlse.fr/2286/.
Der volle Inhalt der QuelleRibosomes constitute one of the major actors of the mechanism of translation in any living cell. The synthesis of ribosomes is a complex process beginning with the transcription of a pre-ribosomal RNA (rRNA) containing future mature rRNAs as well as sequences that are eliminated during ribosome biogenesis. In Saccharomyces cerevisiae, no less than 200 factors are implicated in this process. We were more precisely interested in the cytoplasmic step of the small ribosomal subunit maturation consisting of an endonucleolytic cleavage of the 20S pre-rRNA contained in a pre-40S particle and leading to the mature 18S rRNA contained in the 40S ribosomal subunit. The initial model was that 40S ribosomal subunit maturation might be a pre-requisite for translation initiation. Our experiments have led to the observation that a fraction of 20S pre-rRNA co-sediments with 80S complexes and polysomes. This 20S pre-rRNA fraction can be increased in mutants impaired in the cytoplasmic step of 40S ribosomal subunit maturation. By biochemical approaches, we confirmed the occurrence of ribosomes containing pre-40S particles and mRNAs. Thus, our data suggest that pre-40S particles can initiate translation. These aberrant ribosomes are then degraded via the No Go decay pathway involved in the quality control of some cytoplasmic RNAs. No-Go Decay would function as an ultimate quality control mechanism of the 40S ribosomal subunit
Halladjian, Maral. „Etude de la fonction de l'hélicase Prp43 dans la synthèse des ribosomes et des connexions entre synthèse et maturation du pré-ARN ribosomique chez la levure“. Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30156.
Der volle Inhalt der QuelleIn eukaryotic cells, ribosome synthesis begins with the transcription of ribosomal DNA (rDNA) by RNA polymerase I (Pol I). This process generates a primary transcript (pre-rRNA), containing the sequences corresponding to the mature 18S, 5.8S and 25S rRNAs. The fourth rRNA (5S) is transcribed independently by RNA Pol III. The pre-rRNA associates co-transcriptionally with some ribosomal proteins and many maturation factors to generate a large initial pre-ribosomal particle called the 90S particle. This particle undergoes a complex maturation process generating the pre-40S and pre-60S particles that will generate the mature ribosomal subunits. The first part of my thesis work consisted in the study of the Rpf2-Rrs1 heterodimer in yeast. This heterodimer is known to be essential for the maturation of pre-60S particles through the recruitment of the 5S RNP, a module containing the 5S rRNA associated to ribosomal proteins RpL5 and RpL11. We showed that Rpf2 and Rrs1 interact with rDNA chromatin using chromatin immunoprecipitation (ChIP) experiments and that this interaction does not depend on the integrity of the pre-ribosomal particles. Moreover, both Rpf2 and Rrs1 interact with Pol I subunits and with several rDNA chromatin-associated factors in vivo. These data suggest a function of the Rpf2-Rrs1 heterodimer in the regulation of Pol I transcription in addition to its role in the maturation of pre-60S particles. Interestingly, we observed using Miller spread experiments that loss of expression of Rpf2 or Rrs1 is correlated with strong perturbations in the organization of rDNA units. Using the "run-on" experiment, a technique allowing to determine the occupancy of active polymerases on the rDNA units, I further showed that loss of expression of Rpf2 or Rrs1 strongly affects Pol I transcription in yeast cells. Additional experiments suggest that the Rpf2-Rrs1 complex is present on rDNA units in absence of Pol I transcription in vivo and interacts with purified Pol I in vitro. These data strongly suggest that the Rpf2-Rrs1 heterodimer is a prime candidate to plays a crucial role in the functional coupling between rDNA transcription and pre-ribosome assembly in yeast cells. The second part of my thesis work focused on the study of the Prp43 helicase in yeast. Prp43 is a helicase from the DEAH/RHA family required for both the synthesis of ribosomes and the splicing of pre-mRNAs. Prp43 interacts with G-patch domain-containing proteins which activate its enzymatic activity in vitro by an unknown mechanism. During my thesis, we showed that the activation of Prp43 by G-patch proteins seems to be linked to the unique nucleotide binding mode of this helicase family. Previous structural data showed that the base of the ATP molecule is stacked between two residues, R159 of the RecA1 domain and F357 of the RecA2 domain in the active site of Prp43. The in vitro study of a Prp43 mutant bearing a substitution of F357 to an alanine (F357A) showed that the lack of stacking of the nucleotide base to the F357 residue uncouples the NTPase and helicase activities of Prp43 in vitro. In contrast the substitution of R159 to an alanine (R159A) reduced both the ATPase and helicase activities of the enzyme. We observed in addition that the Prp43 R159A mutation induces the same phenotype as the one resulting from the absence of Gno1, one of the G-patch domain-containing partners of Prp43. This result strongly suggests that the processing defects observed in the absence of Gno1 result from a failure to activate the Prp43 helicase. Overall we propose that the stacking of the ATP base between residues R159 and F357 is important for the activity and regulation of this helicase family
Pantazi, Asimina. „Understanding tumour suppressive responses upon inhibition of ribosome maturation“. Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31416.
Der volle Inhalt der QuelleChoque, Élodie. „Les étapes précoces de la biogenèse du ribosome chez Saccharomyces cerevisiae“. Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1717/.
Der volle Inhalt der QuelleRibosomes are ribonucleoparticles responsible for mRNA translation into protein. In eukaryotes, more than 200 nucleic and proteic factors are required for production and assembly of mature ribosomal subunits. Ribosome biogenesis is a highly complex process including numerous steps, coordinated in time and space. It begins with the rDNA transcription by RNA Pol. I in the nucleolus. Many maturation factors will fit together on the nascent transcript to form the SSU Processome, a pre-ribosomal particle. The proper production of this particle is required for A0, A1 and A2 co-transcriptional cleavages, which lead to the production of small (pre-40S) and large subunit precursors (pre-60S). During my PhD, I have focused to characterize the precise role of two nucleolar proteins, Nop19p (YGR251w) and Efg1p (YGR272c-a), in ribosome biogenesis. I have shown that these factors are physically associated with early pre-ribosomal particles. Their absence lead to the accumulation of an aberrant precursor, 23S pre-rRNA, resulting from a direct cleavage of the nascent transcript in A3. It induces a production defect of the small ribosomal subunit ending to cell death. Nop19p, an essential protein, is required for early A0, A1 and A2 cleavages of the pre-rRNA. Our results show that it is needed for assembly of Utp25p in SSU Processome and for disassociation of RNA helicase Dhr2p after A0, A1and A2 cleavages. Observation of ribosomal particles sedimentation profiles in absence of Efg1p show the emergence of a 50S particle, previously described as a putative intermediate of small subunit. Appearance of this specific particle, in absence of Efg1p, is consistent with 23S pre-rRNA accumulation, whose fate is still in dispute. This 50S particle could be either a specific intermediate of small ribosomal subunit or an improperly assembled SSU Processome to be degraded
Savino, Tulia Maria. „NOP 52, une nouvelle protéine impliquée dans la maturation de l'ARNR : séquence, localisation, recrutement en fin de mitose de nucléole“. Paris 5, 2000. http://www.theses.fr/2000PA05S010.
Der volle Inhalt der QuelleGraindorge, Jean-Sébastien. „Implication de la GTPase Efl1 dans une étape de maturation cytoplasmique des sous-unités 60S de levure“. Université Louis Pasteur (Strasbourg) (1971-2008), 2004. http://www.theses.fr/2004STR13162.
Der volle Inhalt der QuelleRibosomal biogenesis is a complex process that occurs principally in the nucleus but also in the cytoplasm. Works present in this thesis had the elucidation of Efl1 function as an object. Efl1, an homologue of EF-2, is a putative cytoplasmic GTPase implied in 60S subunit biogenesis. EFL1 deletion leads to 60S subunits decrease and defaults in 25S and 5. 8S rRNA processing. On the other hand, a single mutation on TIF6, which codes for a 60S subunit assembling factor, is able to compensate for EFL1 deletion. Tif6 depletion and EFL1 deletion present similar molecular phenotypes. Furthermore Tif6, which is localized in the nucleolus in wild-type strain, is relocated at 50% in the cytoplasm of the Defl1 strain. Those datas allowed us to propose that Efl1 promots Tif6 release from 60S particles during a late cytoplasmic step of 60S biogenesis. After its release, Tif6 is recycled in nucleolus. This model is support by an in vitro test showing that Tif6 is released from 60S particles in the presence of Efl1. We have also shown with in vitro tests that Efl1 is a GTPase whose activity is linked to its binding on the GTPase center domain of ribosomes. To verify if Efl1 can act as a molecular motor to generate structural rearrangements like EF-2, we have probed this region in three contexts : wild-type, revertant and Defl1. We observed conformationnal differences on 60S particles from a Defl1 strain but they seem to be linked to the lack of Tif6 in nucleolus during 60S biogenesis. To finish, analysis by mass spectroscopy of proteinic components from 60S preparticles do not show any assembling factor deficit in the Defl1 context but allowed us to identify three unknown factors
Rouquette, Jacques. „Export nucléaire des pré-ribosomes“. Toulouse 3, 2005. http://www.theses.fr/2005TOU30250.
Der volle Inhalt der QuelleThe ribosome is composed of the 40S subunit (18S rRNA associated with about thirty proteins), and the 60S subunit (5. 8S, 25S/28S and 5S rRNAs and approximatively forty proteins). Different maturation steps take place as pre-ribosomal particles are transported through the nucleus, from the nucleolus to the nucleoplasm, until nucleocytoplasmic translocation. On a first stage, we studied nucleoporins function in pre-40S particle transport using budding yeast mutant strains. This project has given rise to a complete inventory of nucleoporins required in both pre-40S particle and mRNP nucleocytoplasmic trafficking. Translocation of pre-ribosomal particles and mRNPs through the NPC needs distinct nucleoporins complexes, partially overlapping, indicating different export pathways. On a second stage, we extended the study of pre-ribosome transport to mammalian cells. For the first time, we show the existence of a new 18S rRNA precursor, exported to the cytoplasm, like in yeast
Barbezier, Nicolas. „Étude de la synthèse et de la maturation des précurseurs dicistroniques ARNt-snoARN chez Arabidopsis thaliana“. Perpignan, 2006. http://www.theses.fr/2006PERP0762.
Der volle Inhalt der QuelleSmall nucleolar RNAs of class C/D (C/D snoRNAs) represent a large class of small non coding RNAs guiding methylation of ribosomal RNAs and other cellular RNAs. In plants more than a hundred genes have been identified in Arabiodopsis thaliana. Most of them are organised in clusters and expressed as polycistronic precursors that must be processed by endonuclease and exonuclease to liberate the snoRNA. A variation to these, unique to plants, are the dicistronic glycine tRNA-C/D snoRNA genes. In this work, we searched to identify the endonuclease responsible for tsnoRNA maturation and more factors involved in the tsnoRNA synthesis and maturation. To study the transcription and maturation pathway in vivo, we created transgenic plants expressing mutants of these tsnoRNAs. We show that dicistronic tRNA-snoRNA precursor is synthesised by RNA polymerase III system and is further processed to produce the tRNA and the snoRNA separated products. To study this step, we developed nuclear extracts from cauliflower inflorescence that accurately process the dicistronic tsnoRNA precursor in vitro. In addition we have evidence that these extracts allows assembly of the small nucleolar ribonucleoprotein (snoRNP) that is essential for snoRNA stability and activity
Sims, Lynn. „Biochemical Studies of ABCE1“. Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5501.
Der volle Inhalt der QuellePh.D.
Doctorate
Biology
Sciences
Biomedical Sciences
Al, Kadri Yasmine. „Étude de la fonction du complexe Bms1p/Rcl1p dans les étapes précoces de la synthèse des ribosomes et des connexions entre synthèse et maturation du pré-ARN ribosomique chez Saccharomyces cerevisiae“. Toulouse 3, 2014. http://www.theses.fr/2014TOU30099.
Der volle Inhalt der QuelleIn eukaryotic cells, ribosome synthesis begins with the transcription of ribosomal DNA (rDNA) by RNA polymerase I (Pol. I) in the nucleolus. This transcription generates a primary transcript precursor to the mature 18S, 5. 8S and 25S. This transcript is co-transcriptionally associated with some ribosomal proteins, many assembly and maturation factors and a set of small ribonucleoprotein particles to generate a giant initial pre-ribosomal particle. This particle undergoes a complex maturation process which begins in the nucleolus and ends in the cytoplasm where the formation of mature ribosomal subunits occurs. Ribosome synthesis is one of the most energy-consuming cellular processes; it must be highly regulated and tightly coordinated with other fundamental cellular processes. As previously mentioned, ribosome synthesis involves around 200 dedicated to the assembly and maturation of pre-ribosomal particles. However, the function of the vast majority of them is still unknown and current challenges in the field are to understand their precise molecular role. Part of my thesis work consisted in the study of the structure / function of the Bms1p/Rcl1p complex involved in ribosome synthesis in yeast. Rcl1p and Bms1p are two essential nucleolar proteins that form a complex required for the maturation of the small ribosomal subunit (40S). Bms1p is a GTPase and Rcl1p is an endoribonuclease which catalyzes the cleavage of the pre-rRNA at site A2; the step which separates the two maturation pathways leading to the formation of ribosomal subunits 40S and 60S. The team of our collaborator Sébastien Fribourg (IECB, Bordeaux) has solved the crystal structure of Rcl1p in complex with a fragment of Bms1p and identified residues at the interface between the two proteins. The substitution of some of these amino acids affects the interaction between Rcl1p and Bms1p in vitro and induces defects in the maturation of pre-rRNA in vivo. We have shown that these defects are probably due to a problem in Rcl1p incorporation into pre-ribosomal particles. Indeed, Bms1p and Rcl1p are imported into the nucleus as a complex via the nuclear localization sequence (NLS) of Bms1p. Both proteins are then recruited simultaneously into pre-ribosomes after incorporation of UTP-A and UTP-B modules but independently of Rrp5p incorporation. Our results also suggest that the GTP-binding to Bms1p is not required for the recruitment of the complex. Following A2 cleavage, the two proteins are both released from pre-40S particles before Rio2p incorporation. Therefore, our data indicate that the direct interaction between Bms1p and Rcl1p is crucial for the incorporation of the complex into pre-ribosomes in yeast. Another part of my thesis work focused on the study of Rpf2p protein, a component of the pre-60S ribosomal particles required for the synthesis of the large ribosomal subunit. Various data from the literature suggest that Rpf2p interacts with rDNA chromatin associated factors. We have confirmed some of these interactions and our results suggest that Rpf2p is associated in vivo with rDNA chromatin and more particularly to transcriptionally active copies. These data suggest that Rpf2p could be involved in mechanisms of chromatin modification required for transcription by RNA Pol. I and indeed, nuclear "run-on" experiments indicate that the loss of Rpf2p expression affects transcription by RNA pol. I. These preliminary results suggest that Rpf2p could be involved in the functional coupling between rDNA transcription and maturation of pre-ribosomal particles
Clery, Antoine. „Etude structurale et fonctionnelle de motifs en "K-turn" présents dans les ARN, rôle dans l'assemblage et le mécanisme d'action de particules ribonucléoprotéiques impliquées dans la maturation des ARN“. Nancy 1, 2006. http://www.theses.fr/2006NAN10108.
Der volle Inhalt der QuelleIn eukarya, the nucleolar U3 snoRNP plays a crucial role in 18S rRNA maturation. U3 snoRNA contains 2 domains (5' and 3'). We studied the role for 18S rRNA production of base-pair interactions formed between its 5' domain and the pre-rRNA. U3 snoRNA binds several proteins. Its 3' domain contains two protein anchoring sites (the C'/D and B/C motifs). They adopt a peculiar K-turn structure and each K-turn binds protein Snu13. Binding of this protein is required for recruitment of proteins Nop1, Nop56 and Nop58 on the C'/D motif and of protein Rrp9 on the B/C motif. We determined the RNA determinants, required for the specific recruitment of these proteins, in particular Rrp9p. The RNA binding domain of protein Snu13p has strong homologies with those of the archaeal L7Ae and vertebrate SBP2 proteins. We compared the RNA binding specificity of these 3 proteins. Finally, we studied RNA conformational changes in pre-ribosomal RNAs during the maturation process
Raoelijaona, Raivoniaina. „Compréhension des rôles des complexes Nob1/Pno1 et RPS14/Cinap dans la maturation cytoplasmique de la petite sous-unité ribosomique (pré-40S) chez les eucaryotes“. Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0221/document.
Der volle Inhalt der QuelleRibosomes are translational machineries universally responsible of protein synthesis. In eukaryote, ribosome assembly is a complex and highly regulated process that requires coordinated action of more than 200 biogenesis factors. Ribosome assembly is initiated in the nucleolus, continues in the nucleoplasm and terminates in the cytoplasm. The cytoplasmic maturation events of the small ribosomal subunit are associated with sequential release of the late assembly factors and concomitant maturation of the pre-rRNA. During final maturation of the small subunit, the pre-18S rRNA is cleaved off by the endonuclease Nob1, which activity is coordinated by its binding partner Pno1. Detailed information on pre-ribosomal particle architectures have been provided by structural snapshots of maturation events. However, key functional aspects such as the architecture required for pre-rRNA cleavage have remained elusive. In order to better understand these late steps of cytoplasmic pre-40S maturation, we first redefine the domain organization of Nob1, then study its binding mode with Pno1 using different tools such as sequence analysis, structure prediction and biochemical experiments and, we then performed functional assay to elucidate the role played by Pno1 during the pre-18S rRNA maturation.Our results have shown that eukaryotic Nob1 adopts an atypical PIN domain conformation: two fragments (res 1-104 and 230-255) separated by an internal loop, which is essential for Pno1 recognition. We also found out that Pno1 inhibits Nob1 activity likely by masking the cleavage site. Our findings further support the recently published cryo-EM structure of the pre-40S, where Nob1 displays an inactive conformation. Moreover, 18S rRNA 3’-end cleavage has to happen and this implies structural rearrangement or requirement of some accessory proteins such as Cinap, an atypical kinase involved in pre-18S processing. Studying the interplay between proteins localized in the pre-40S platform (RPS14, RPS26, Nob1/Pno1 complex) has shown that Cinap is able to form a trimeric complex with Nob1 and its binding partner Pno1. Furthermore, Cinap can recognize RPS26 in a RPS14-dependent manner, which had already been studied with its yeast counterpart. It is important to note that RPS26 is the ribosomal protein replacing Pno1 in the mature ribosome. Our finding clearly suggests a mechanism where RPS26 recruitment to the ribosome requires Pno1 dissociation. This exchange would be carried out by Cinap. Therefore, we can suggest a simplified model as follow: upon binding with Pno1, the newly formed complex (Cinap/Pno1) will trigger a conformational change, which will allow the endonuclease Nob1 to reach its substrate (D-site) and perform its cleavage resulting in mature 18 rRNA generation
Torchet, Claire. „Etude du role particulier joue par le gene rrp5 dans la maturation des arn ribosomaux chez la levure saccharomyces cerevisiae“. Paris 11, 2000. http://www.theses.fr/2000PA112120.
Der volle Inhalt der QuelleFayet-Lebaron, Eléonore. „Caractérisation de la fonction moléculaire du petit ARN nucléolaire H-ACA, snR30, dans la biogenèse des ribosomes chez Saccharomyces cerevisiae“. Toulouse 3, 2009. http://thesesups.ups-tlse.fr/1246/.
Der volle Inhalt der QuelleRibosome synthesis takes place in the nucleolus where many box H/ACA snoRNAs direct pseudouridylation of rRNAs. The U17/snR30 box H/ACA snoRNA, instead of directing rRNA modification, functions in the nucleolytic processing of the precursor rRNA (pre-rRNA) and is required for accumulation of mature 18S rRNA. We have identified two short sequence motifs in the 18S rRNA that can base-pair with two evolutionarily conserved sequences elements, m1 and m2 motifs, of the yeast Saccharomyces cerevisiae snR30. Mutations in the 18S sequences disrupting the base-pairing with the m1 or m2 motifs of snR30 inhibit the accumulation of the mature 18S rRNA. However, compensatory mutations introduced into m1 or m2 motifs of snR30 restore 18S rRNA processing. The m1 and m2 motifs that constitute the opposite strands of an internal loop of U17/snR30 base-pair with short 18S sequences preceding and following a conserved stem-loop structure in the middle of the 18S rRNA. Further functional mapping of yeast snR30 indicated that its 3'-terminal hairpin contains additional essential elements. Thus I developed a novel tandem affinity purification method in order to identify the putative snR30-specific snoRNP proteins
Fils-Lycaon, Bernard. „Maturation et postmaturation de la cerise (prunus avium l. , var. Bigarreau napoleon) sur l'arbre : caracterisation physico-chimique, synthese proteique, degagements gazeux“. Orléans, 1988. http://www.theses.fr/1988ORLE2003.
Der volle Inhalt der QuelleDavila, Gallesio Jimena [Verfasser], Markus [Akademischer Betreuer] Bohnsack, Jörg [Gutachter] Enderlein, Gerhard [Gutachter] Braus, Blanche [Gutachter] Schwappach, Michael [Gutachter] Meinecke, Michael [Gutachter] Thumm und Ralf [Gutachter] Ficner. „The roles of RNA helicases and other ribosome biogenesis factors during small subunit maturation / Jimena Davila Gallesio ; Gutachter: Jörg Enderlein, Gerhard Braus, Blanche Schwappach, Michael Meinecke, Michael Thumm, Ralf Ficner ; Betreuer: Markus Bohnsack“. Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1211556816/34.
Der volle Inhalt der QuelleClerget, Guillaume. „Caractérisation des propriétés d’un mutant de la protéine Rrp9p de la snoRNP U3 de levure Saccharomyces cerevisiae et mise en évidence d’un réseau de protéines au sein du complexe de maturation précoce des ARNr“. Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0315/document.
Der volle Inhalt der QuelleRibosome biogenesis is a complex and dynamic process requiring several assembly and maturation factors needed for processing of the pre-rRNA and assembly of the ribosomal protein. In eukarya, biogenesis of the 40S small subunit starts in the nucleolus with the transcription of a long pre-rRNA, containing 3 out of the 4 future rRNAs. The 18S pre-rRNA is modified by several C/D or H/ACA box snoRNPs and processed by endonucleolytic cleavages at sites A0, A1 and A2 sites. These early cleavages occur within a huge complex termed the SSU-processome. The processome assembles at the 5’ extremity of the pre-rRNA, and contains multiple factors, including the U3 snoRNP, a C/D box snoRNP chaperoning the pre-rRNA. Indeed, the U3 snoRNA is involved in formation of 5 intermolecular helix with the pre-rRNA, which defines the A0, A1 and A2 cleavage sites. In addition to the four C/D box snoRNP core proteins, the U3 snoRNP contains additional protein, Rrp9p, required for cell viability. The Rrp9p C-terminal extremity folds into a beta propeller structure. To try to decipher the Rrp9p role, we mutated several surface residues of the beta propeller protein and the effects of the mutations on cell growth were tested. Through this approach, we found that the R289 residue is important for the maturation events at A1 and A2 sites. Moreover, we identified new protein partners of Rrp9p within the processome and showed that R289 residue is involved in a direct interaction with Rrp36p. We identified a network of protein-protein interactions including Rrp9p, Rrp36p, Sgd1p and Rrp5p : Rrp9p interacts with Rrp36p and Sgd1p, Rrp36p and Sgd1p interact together and with Rrp5p. Some of the protein domains involved in the interactions were identified. In addition, the R289A mutation in Rrp9p has a strong negative effect on growth with mutations in U3 snoRNA that destabilize the U3 snoRNA/pre-rRNA interaction
Bussiere, Cyril Luc Cassien. „Late cytoplasmic maturation of the large ribosomal subunit“. Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-2811.
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Lo, Kai-Yin 1978. „Nuclear export and cytoplasmic maturation of the large ribosomal subunit“. 2009. http://hdl.handle.net/2152/10682.
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Kallstrom, George Harvester. „Defining the late 60S ribosomal subunit maturation pathway from the nucleolus to the cytoplasm“. 2002. http://wwwlib.umi.com/cr/utexas/fullcit?p3101216.
Der volle Inhalt der QuelleTai, Lin-ru, und 戴伶如. „Crucial role of the cytoplasm nature of human ribosomal protein S20 for the maturation and functioning of the eukaryotic small subunit ribosome“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/19586010372465789780.
Der volle Inhalt der Quelle國立陽明大學
生命科學系暨基因體科學研究所
102
By Western blotting analysis and the immunofluorescence microscopy observation, we identified that ribosomal protein S20 is a cytoplasmic protein. To view the importance of the cytoplasm nature of S20, we created a nuclear resident S20NLS mutant protein and examined its behavior with respect to small subunit assembly and function. Using an energy depletion and recovery approach to shuttle S20NLS between the nucleus and the cytoplasm, we showed that the joining of S20 to the pre-40S subunit in the cytoplasm was essential for creating a functional small subunit. In addition, we demonstrated that the cytoplasm nature of S20 was required for the late maturation of 18S rRNA using a combining approach of the siRNA knock-down and a co-transfection assay. Furthermore, the Arg62, Arg83, and Arg87 within the putative β-stranded ribbon structure of S20 were involved in the maturation. Our results suggest that the late joining of S20 in the cytoplasm is crucial for 18S rRNA maturation and for making a functionally proficient subunit. It also implies that the order of eukaryotic ribosomal protein assembly may probably execute in a similar order as imposed by the rules of the prokaryotic ribosome map.
Aguilar, Lisbeth C. „Uncovering parallel ribosome biogenesis pathways during pre-60S subunit maturation“. Thèse, 2014. http://hdl.handle.net/1866/11288.
Der volle Inhalt der QuelleLes paralogues sont présents lors de la biogenèse des ribosomes ainsi que dans les ribosomes matures sous forme de protéines ribosomiques, et sont généralement censées jouer des fonctions redondantes dans la cellule. Deux paralogues précédemment identifiées sont la paire de protéines Ssf1 et Ssf2 (94 % d'homologie). Ssf2 remplacerait Ssf1 en cas d’absence du dernier dans la cellule, et l’absence des deux protéines diminue la croissance cellulaire. Nos résultats révèlent que, dans des conditions normales, les paralogues Ssf s’associent à des ensembles de protéines similaires, mais avec différentes stabilités. De plus, la perturbation de leurs particules pré-rRNP à l’aide de tampons de haute stringence a révélé qu'au moins trois protéines, probablement Dbp9, Drs1 et Nog1, sont fortement associées à chaque protéine Ssf dans ces conditions, et très probablement représentent des sous-complexes distincts. Dans cette étude, les phénotypes cellulaires observés lors de la déplétion des protéines Nop7, Ssf1 et/ou Ssf2 ont révélé que les paralogues Ssf ne peuvent pas compenser entièrement pour la diminution de l'autre, car ils sont, indépendamment l’un de l’autre, nécessaires le long de voies de biogénèse ribosomale parallèles qui dépendent des niveaux de protéines impliqués dans la biogénèse des ribosomes disponibles. Enfin, ce travail fournit des preuves que, dans la levure, Nop7 est génétiquement lié aux deux protéines Ssf.
Cléroux, Katherine. „Dissecting the dynamic of Noc2p and its partners in pre-60S particles maturation“. Thèse, 2014. http://hdl.handle.net/1866/11823.
Der volle Inhalt der QuelleSeveral studies have been performed to characterize the ribosome as far as to understand its structure and its function. However, major aspects of ribosome biogenesis remain elusive or gave only a static picture of the process. In fact, ribosome biogenesis involves dynamic processing and assembly pathways that are required for rRNA modification and folding, in addition to rRNA binding with some ribosomal proteins. One set of assembly factors, the Noc proteins, allowed one of the first indications about the spatio-temporal ordering of ribosome maturation. By using yeast as model, our objective is to provide a dynamic picture of the Noc proteins complexes exchange and nuclear localization by determining the nature of Noc2p interactions with Noc1p and Noc3p and by studying the influence of reversibly arrested intranuclear transport on these proteins and on Rix7p, an AAA-ATPase. In order to achieve these aims, inducible promoter, fluorescent microscopy, western blot, qRT-PCR and affinity purification analyses were used.
Davila, Gallesio Jimena. „The roles of RNA helicases and other ribosome biogenesis factors during small subunit maturation“. Doctoral thesis, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0005-13BE-0.
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