Control of Early Germline Development in C. elegans

描述（由申请人提供）：生殖细胞负责物种的繁殖和延续，因此在发育中起着关键作用。我们正在研究的机制，保持生殖细胞的不朽性，并指导其独特的发展计划，使用遗传学，基因组学，分子和生物化学方法相结合的模型系统秀丽隐杆线虫。我们以前确定了四个C。线虫MES蛋白是生殖细胞永生所必需的。MES-2、MES-3和MES-6构成蠕虫中染色质调节剂的Polycomb组，作为复合物起作用，并参与维持X染色体在大部分种系发育中处于沉默状态。MES-4与常染色体结合，并可能起保护常染色体免于沉默的作用。MES系统在染色质中组蛋白尾部的修饰水平上操作。MES-2/3/6复合物催化抑制基因表达的组蛋白H3 Lys 27的甲基化。该提案的目标是：a）阐明MES-3和MES-6以及可能的MES-6的替代配偶体如何影响MES-2的组蛋白甲基化，B）测试我们的预测，即MES-4也起甲基化组蛋白的作用，并鉴定与MES-4一起作用的其他蛋白质，c）研究MES-4如何特异性靶向常染色体，d）鉴定其表达受MES-2/3/6和MES-4调节的一些基因，和e）确定MES- 2/3/6和MES-4如何相互作用以及如何与SynMuv类染色质调节剂相互作用。染色质组织的动态调节是控制基因表达和发育的关键水平，并且已知失调有助于疾病状态和癌症。我们的研究将为了解染色质状态的控制，常染色体和性染色体之间的区分机制，以及生殖细胞中特定的染色质要求做出重要贡献。

DESCRIPTION (provided by applicant): Germ cells are responsible for the fertility and perpetuation of species and thus serve a key role in development. We are investigating the mechanisms that preserve the immortality of germ cells and guide their unique developmental program, using a combination of genetics, genomics, and molecular and biochemical approaches in the model system Caenorhabditis elegans. We previously identified four C. elegans MES proteins as being required for germ cell immortality. MES-2, MES-3, and MES-6 constitute the Polycomb Group of chromatin regulators in worms, operate as a complex, and participate in maintaining the X chromosomes in a silenced state throughout most of germline development. MES-4 binds the autosomes and may function to protect them from silencing. The MES system operates at the level of modification of histone tails in chromatin. The MES-2/3/6 complex catalyzes methylation of histone H3 Lys27, which represses gene expression. The goals of this proposal are to: a) elucidate how MES-3 and MES-6 and perhaps an alternative partner to MES-6 influence histone methylation by MES-2, b) test our prediction that MES-4 also functions to methylate histones and identify other proteins that operate with MES-4, c) investigate how MES-4 is targeted specifically to the autosomes, d) identify some of the genes whose expression is regulated by MES-2/3/6 and MES-4, and e) determine how MES- 2/3/6 and MES-4 interface with each other and with the SynMuv class of chromatin regulators. The dynamic regulation of chromatin organization is a crucial level of control of gene expression and development, and misregulation is known to contribute to disease states and cancers. Our studies will make important contributions to understanding control of chromatin states, mechanisms for discriminating between the autosomes and the sex chromosomes, and specific chromatin requirements in germ cells.