The cell cycle timing of centromeric chromatin assembly in Drosophila meiosis is distinct from mitosis yet requires CAL1 and CENP-C.
The cell cycle timing of centromeric chromatin assembly in Drosophila meiosis is distinct from mitosis yet requires CAL1 and CENP-C.
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DOI：
10.1371/journal.pbio.1001460
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发表时间：
2012
期刊：
影响因子：
9.8
通讯作者：
Karpen GH
中科院分区：
文献类型：
--
作者：
Dunleavy EM;Beier NL;Gorgescu W;Tang J;Costes SV;Karpen GH
着丝粒组蛋白CENP-A在果蝇体细胞有丝分裂、减数分裂I和减数分裂II的不同细胞周期阶段被掺入。CENP-A（CID在苍蝇）是组蛋白H3变异体的着丝粒规范，动粒形成，和染色体分离在细胞分裂过程中必不可少的。最近的研究已经阐明了主要的细胞周期机制和关键因素CENP-A纳入有丝分裂，主要是在培养的细胞。然而，我们不了解CENP-A组装在多细胞生物体组织和减数分裂中的作用、调节和细胞周期定时，减数分裂是产生单倍体配子的专门细胞分裂周期。在这里，我们调查的时机和要求CID组装有丝分裂组织和男性和女性减数分裂的果蝇，使用固定和活成像结合遗传学方法。我们发现，CID大会开始在末期，并继续在G1期在体细胞组织中的生物体，晚于中期大会观察到在培养细胞。此外，CID组装发生在两个不同的细胞周期阶段，在男性减数分裂：减数分裂I的前期和退出减数分裂II后，在精子细胞。在前期I中的CID组装在雌性减数分裂中也是保守的。有趣的是，我们观察到一个新的CID水平下降后，减数分裂I结束和减数分裂II之前，这在时间上与动粒组织和方向的变化。我们还表明，CID保留在成熟精子，尽管总染色质重塑发生在鱼精蛋白交换。最后，我们表明，着丝粒蛋白CAL 1和CENP-C都需要CID组装在减数分裂和精子发生的正常进展。我们的结论是，CID大会在减数分裂的细胞周期的时间是不同的有丝分裂和CID通过减数分裂和精子的有效传播可能是重要的着丝粒规格在发展中的合子。着丝粒是真核生物染色体的区域，其募集动粒并且在所有细胞分裂期间对于DNA的忠实分离是必不可少的。着丝粒特异性组蛋白H3变体CENP-A在着丝粒处积累，限定该区域，并且在大多数真核生物中通过表观遗传机制在整个细胞世代中维持。以前的研究已经发现了许多因素调节CENP-A的维持和组装在着丝粒在有丝分裂过程中在培养细胞，但在动物组织中的减数分裂和有丝分裂过程中的CENP-A组装的调节模式是未知的。在这项研究中，我们使用果蝇作为一个有机体模型，以调查的时间和要求的CID，苍蝇CENP-A同源组装。我们发现CID在脑干和非干细胞的终末期/G1期装载在着丝粒上。在雄性减数分裂中，CID在两个阶段加载，在减数分裂I的第一阶段期间和在第二次减数分裂之后。减数分裂I加载时间在雌性中也是保守的。我们还报告了一个前所未有的下降CID水平减数分裂后，我和减数分裂前II，这与动粒重定向的时间。此外，我们发现两个基本的着丝粒蛋白（CAL 1和CENP-C）是必要的CID组装和染色体分离在减数分裂。我们的数据表明，在整个生物体的有丝分裂和减数分裂期间，CENP-A组装的新的差异时间。
The centromeric histone CENP-A is incorporated at different cell cycle phases during somatic mitosis, meiosis I and meiosis II in Drosophila melanogaster. CENP-A (CID in flies) is the histone H3 variant essential for centromere specification, kinetochore formation, and chromosome segregation during cell division. Recent studies have elucidated major cell cycle mechanisms and factors critical for CENP-A incorporation in mitosis, predominantly in cultured cells. However, we do not understand the roles, regulation, and cell cycle timing of CENP-A assembly in somatic tissues in multicellular organisms and in meiosis, the specialized cell division cycle that gives rise to haploid gametes. Here we investigate the timing and requirements for CID assembly in mitotic tissues and male and female meiosis in Drosophila melanogaster, using fixed and live imaging combined with genetic approaches. We find that CID assembly initiates at late telophase and continues during G1 phase in somatic tissues in the organism, later than the metaphase assembly observed in cultured cells. Furthermore, CID assembly occurs at two distinct cell cycle phases during male meiosis: prophase of meiosis I and after exit from meiosis II, in spermatids. CID assembly in prophase I is also conserved in female meiosis. Interestingly, we observe a novel decrease in CID levels after the end of meiosis I and before meiosis II, which correlates temporally with changes in kinetochore organization and orientation. We also demonstrate that CID is retained on mature sperm despite the gross chromatin remodeling that occurs during protamine exchange. Finally, we show that the centromere proteins CAL1 and CENP-C are both required for CID assembly in meiosis and normal progression through spermatogenesis. We conclude that the cell cycle timing of CID assembly in meiosis is different from mitosis and that the efficient propagation of CID through meiotic divisions and on sperm is likely to be important for centromere specification in the developing zygote. Centromeres are regions of eukaryotic chromosomes that recruit the kinetochores and are essential for faithful segregation of DNA during all cell divisions. The centromere-specific histone H3 variant CENP-A accumulates at the centromere, defining this region, and is maintained throughout cellular generations by epigenetic mechanisms in most eukaryotes. Previous studies have discovered many factors regulating both the maintenance and assembly of CENP-A at centromeres during mitosis in cultured cells, but the mode of regulation of CENP-A assembly during meiosis and mitosis in animal tissues is unknown. In this study, we use Drosophila melanogaster as an organismal model to investigate the timing and requirements for assembly of CID, the fly CENP-A homolog. We find that that CID is loaded at centromeres during telophase/G1 phase in brain stem and nonstem cells. In male meiosis, CID is loaded in two phases, during the first stages of meiosis I and after the second meiotic division. Meiosis I loading time is also conserved in females. We also report an unprecedented drop in CID levels after meiosis I and before meiosis II, which correlates with the timing of kinetochore reorientation. Additionally, we find that two essential centromere proteins (CAL1 and CENP-C) are necessary for CID assembly and chromosome segregation during meiosis. Our data demonstrate novel differential timing for CENP-A assembly during mitosis and meiosis in the whole organism.
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DOI：
10.1073/pnas.0500172102
发表时间：
2005-03-22
影响因子：
11.1
作者：
Anderson, LK;Royer, SM;Hawley, RS
通讯作者：
Hawley, RS
影响因子：
7.8
作者：
Jansen, Lars E. T.;Black, Ben E.;Foltz, Daniel R.;Cleveland, Don W.
通讯作者：
Cleveland, Don W.
DOI：
10.1083/jcb.201012017
发表时间：
2011-07-25
期刊：
The Journal of cell biology
影响因子：
--
作者：
Barnhart MC;Kuich PH;Stellfox ME;Ward JA;Bassett EA;Black BE;Foltz DR
通讯作者：
Foltz DR
影响因子：
4.5
作者：
Lake CM;Nielsen RJ;Hawley RS
通讯作者：
Hawley RS
DOI：
10.1186/bcr3181
发表时间：
2012-05-04
期刊：
Breast cancer research : BCR
影响因子：
--
作者：
McGovern SL;Qi Y;Pusztai L;Symmans WF;Buchholz TA
通讯作者：
Buchholz TA