CONTROL OF EARLY GERMLINE DEVELOPMENT IN C ELEGANS

斯特罗姆博士建议继续她正在进行的关于 对细菌的发育和永久存在至关重要的控制机制 线虫中的细胞，利用其复杂的 遗传学和基因组测序。该提案侧重于两个独立但相关的 生殖细胞功能方面：1)生殖系特有的富RNA颗粒，称为P 颗粒和2)胚系生存所需的一组蛋白质(MES 蛋白质)。拟议中的磷颗粒研究是基于在 Stome博士的PGL-1蛋白实验室，一种可能与RNA结合的P颗粒蛋白 是生殖系发育所必需的。在初步研究中，她有 鉴定了两个与PGL-1和PGL-1序列相似的新的P颗粒蛋白 与PGL-1结合提示一个PGL蛋白家族在P 颗粒。她将确定PGL蛋白的哪些区域将它们招募到 P颗粒，以及哪些生殖系过程需要PGL复合体。她也有 发现PGL-1可以与真核生物的生殖系丰富的异构体结合 翻译起始因子4E(IFE1)，增加了P 颗粒控制特定mRNAs的翻译。她将决定是否 IFE-1是P颗粒的一种成分，当IFE-1出现时，哪些生殖系过程失败 都被淘汰了。她还将识别与P颗粒相关的RNA，并用它们来 P颗粒功能的测试模型，即传递、稳定和控制 生殖系mRNA的翻译。四种MES蛋白，也在 Strome的实验室，是正常的早期发育和生存所必需的 生殖系。基于三个MES蛋白与成员的相似性 转录调控的多梳基团，关于分子上位性 结果，根据转基因在生殖系中的表达分析，她提出 MES蛋白在复合体中工作以控制染色质组织 和基因在早期生殖系中的表达，以及生殖系在 MES突变是由于基因表达模式的异常所致。她将测试这一点 通过确定MES突变种系是否表现出改变的模式进行假说 基因表达，并通过研究MES蛋白是否通过 组蛋白脱乙酰化的控制。一种新的基因筛查也将用于 确定MES介导的调控中涉及的新组件。

Dr. Strome proposes to continue her ongoing investigations of control mechanisms that are essential for development and perpetuation of germ cells in the nematode C. elegans, taking advantage of its sophisticated genetics and sequenced genome. The proposal focuses on two separate but related aspects of germ cell function: 1) germ-line-specific RNA-rich granules called P granules and 2) a set of proteins required for survival of the germ line (MES proteins). The proposed studies of of P granules are based on the discovery in Dr. Stome's lab of PGL-1 protein a putative RNA binding P-granule protein that is required for germ-line development. In preliminary studies she has identified two new P-granule proteins that are similar in sequence to PGL-1 and bind to PGL-1 suggesting that a family of PGL proteins multimerize in P granules. She will determine which regions of the PGL proteins recruit them to P granules, and which germline processes require the PGL complex. She has also found that PGL-1 can bind to a germline-enriched isoform of eukaryotic translation initiation factor 4E (IFE1), raising the possibility that P granules control the translation of specific mRNAs. She will determine whether IFE-1 is a component of P granules and which germline processes fail when IFE-1 is eliminated. She will also identify P-granule-associated RNAs and use them to test models of P-granule function, namely delivery, stabilization, and control of translation of germline mRNAs. Four MES proteins, also discovered in Strome's lab, are required for normal early development and survival of the germline. Based on the similarity of three of the MES proteins to members of the Polycomb Group of transcriptional regulators, on molecular epistasis results, and on assays of transgene expression in the germline, she proposes that the MES proteins operate in complexes to control chromatin organization and gene expression in the early germline, and that death of the germline in mes mutants is due to aberrant patterns of gene expression. She will test this hypothesis by determining whether mes mutant germlines show altered patterns of gene expression, and by investigating whether MES proteins function through control of histone deacetylation. A novel genetic screen will also be used to identify new components involved in MES-mediated regulation.