Human post-translational protein modifier protein SUMO-1/2/3 genes code for proteins homologous to yeast SMT3 protein, which is encoded by a suppressor 3 of MIF2 mutation in centromere protein gene. The yeast MIF2 protein shares at least two regions of similarity with mammalian centromere protein CENP-C. It would be of interest to investigate the possible interaction(s) between human CENP-C and SUMO-1/2/3 proteins. A CENP-C cDNA fragment was cloned using RT-PCR with total RNAs form Hela cells. This cDNA fragment encoding CENP-C amino acids 342-764 (MW 38 kDa designated C38) was tagged with EGFP. The sub-cellular localization and in vivo sumoylation in HeLa cells were carried out. The EGFP-C38 protein was shown to co-localize with active forms of Flag-SUMO-1/2/3GG proteins in nucleus of Hela cells. The EGFP -C38 protein was also shown co-immunoprecipitated with antibodies against SUMO proteins. The protein conjugates were analyzed on SDS-PAGE and their western blots were probed with either anti-GFP or anti- Flag antibodies. The molecular weight of EGFP-C38 protein was found to be higher than the expected MW, indicating that EGFP-C38 protein was sumoylized. This part ( 333 amino acids) of CENP-C protein (943 amino acids) was expressed and purified. The in vitro sumoylized His-C38 protein fragment was analyzed on SDS-PAGE, and the western blot was probed with either anti-SUMO-1 or anti-SUMO-2 antibodies. The C38-His protein fragment appeared to be sumoylized, and the isopeptide bond between the C-terminal glycine of SUMO and lysine of His-C38 was analyzed by MALDI-TOF-TOF. C38 cDNA was sub-fragmented into C28 and C10 fragments transformed to BL21 strain for expression protein and purified protein. S-tagged SUMO-1/2GG modify C28-His and C10-His fragments, the isopeptide bond between the C-terminal glycine of S-tagged SUMO-2GG and lysine of C10-His was identified analyzed by MALDI-TOF-TOF. The isopeptide bonds between either S-tagged SUMO-1GG and C28-His or S-tagged SUMO-1/2GG and C28-His /C10-His are being analyzed.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-08-15T17:53:44Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) A_Marques_PhD_thesis_2016_FINAL.pdf: 9324057 bytes, checksum: 92c1de27f6fa947d7e6b3e74ae09a849 (MD5) / Made available in DSpace on 2016-08-15T17:53:46Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) A_Marques_PhD_thesis_2016_FINAL.pdf: 9324057 bytes, checksum: 92c1de27f6fa947d7e6b3e74ae09a849 (MD5) Previous issue date: 2015-02-15 / capes / Cromossomos holocêntricos são caracterizados pela ausência de constrição primária e apresentam normalmente a proteína centromérica CENH3 distribuída ao longo de um eixo em cada cromátide. Embora muitos organismos com cromossomos monocêntricos apresentem sequências de DNA centroméricas específicas e associadas com a CENH3, nenhuma sequência centromérica havia sido identificada em organismos com cromossomos holocêntricos até o momento. Além disso, vários estudos reportam adaptações meióticas em espécies com cromossomos holocêntricos. Sendo observada em alguns casos uma inversão da ordem dos eventos meióticos (meiose invertida ou pós-reducional). Assim, o presente trabalho objetivou estudar a organização centromérica e a meiose de espécies com cromossomos holocêntricos do gênero Rhynchospora (Cyperaceae). Foi realizada uma análise citogenômica da organização e composição dos holocentrômeros de Rhynchospora pubera (2n = 10), sendo reportada a primeira descoberta de sequências centroméricas em espécies com cromossomos holocêntricos. Foi observado que os holocentrômeros de R. pubera são compostos principalmente por arranjos de DNA satélite (Tyba) e retroelementos centroméricos (CRRh) distribuídos pelo genoma. A análise detalhada da sucessão dos eventos meióticos de R. pubera e R. tenuis (2n = 4) reportou uma prófase inicial semelhante a de monocêntricos. No entanto, foi verificado que as cromátides-irmãs separam para polos opostos durante a anáfase I e os homólogos segregam somente durante a meiose II, comprovando uma meiose invertida para ambas as espécies. Curiosamente, durante a meiose de R. pubera foi observado uma organização diferencial dos centrômeros. Ao contrário do observado em mitose, durante meiose não foi observado a formação de holocentrômeros em forma de linha, sendo, na verdade, observado estruturas centroméricas aglomeradas. O restabelecimento de holocentrômeros em forma de linha se deu durante a primeira mitose do pólen. / Holocentric chromosomes are characterized by the absence primary constriction and normally show the centromeric protein CENH3 distributed along the axis of each chromatid. Although many monocentric organisms show centromere-specific DNA sequences associated to CENH3, no centromeric sequences had been identified in any holocentric organism so far. Furthermore, many studies report meiotic adaptations in holocentric species. In some cases is observed an inversion of the order of meiotic events. This type of meiosis has been named of inverted or post-reductional meiosis and would be exclusive of holocentric organisms. Thus, the present work aimed to study the centromere organization and meiosis of holocentric species of the genus Rhynchospora (Cyperaceae). A cytogenomic analysis of the composition and organization of the holocentromeres of Rhynchospora pubera (2n = 10) has been performed, being reported the first centromeric sequences from a holocentric species. It was observed that the holocentromeres of R. pubera are composed mainly by arrays of satellite DNA (Tyba) and centromeric retrotransposons (CRRh) distributed genomewide. The detailed analysis of the succession of meiotic events of R. pubera and R. tenuis (2n = 4) demonstrated an early meiotic prophase similar to that of monocentric. However, it was verified that sister chromatids separate to opposite poles during anaphase I, while homologs only segregate at meiosis II. These results prove the inverted meiosis for both species. Curiously, it was observed during meiosis of R. pubera a differential organization of centromere units. In contrast to the observed in mitosis, during meiosis we did not observed the formation of line-like holocentromeres, being in fact observed the formation of cluster-like holocentromeres. The reestablishment of a line-like holocentromere occurred during the first pollen mitosis.

京都大学 / 0048 / 新制・論文博士 / 博士(生命科学) / 乙第13256号 / 論生博第18号 / 新制||生||54(附属図書館) / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 松本 智裕, 教授 石川 冬木, 教授 上村 匡 / 学位規則第4条第2項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM