Molecular and Genetic Analysis of Germline Development in C. Elegans

0077172主要研究动物发育过程中细胞命运的调控。实验的重点是如何在模式生物秀丽线虫的生殖系组织中调节细胞增殖。线虫的生殖系增殖是由体细胞性腺细胞发出的信号刺激的。收到信号的生殖细胞将分裂，而没有收到信号的生殖细胞将停止分裂，转而分化为精子或卵子。这种信号通过“Notch-type”生化途径发生。在不同的动物物种中，缺口类型的信号通路调节发育；在哺乳动物中，它们与某些癌症和其他疾病有关。许多问题仍然存在，关于线虫生殖系增殖的调控，以及Notch类型的信号如何激发特定的细胞反应。例如，人们对通路活性的目标或如何调节通路活性知之甚少。线虫生殖系中可能的靶点包括促进配子形成的基因，如GLD-1和GLD-2。Noch型信号转导通过关闭GLD-1和GLD-2基因表达促进细胞增殖。为了更好地了解生殖系发育是如何受到调控的，缅因州博士和他的同事们识别并研究了与信号通路的已知组成部分GLP-1在基因上相互作用的基因。在这里，缅因州博士建议扩大对几个“自我”(GLP-1增强子)基因的分析。缅因州实验室之前的研究表明，EGO-1基因的活性对生殖系发育和一种鲜为人知的称为RNA沉默的过程都是至关重要的。RNA沉默是一种在植物、动物和真菌中观察到的基因调控手段。它被认为是抵御病毒感染的一种防御手段，但P.I.有数据表明，它可能也是发育过程中的一种重要调控机制。因此，她建议研究在生殖系发育过程中可能受到RNA沉默调控的潜在靶基因，包括GLD-1和GLD-2。一些补充研究将探讨(1)EGO-1蛋白在胚系发育过程中的表达，(2)EGO-1是否对与RNA沉默相关的现象是必需的，(3)EGO-1与参与RNA沉默的其他基因之间潜在的遗传相互作用，以及(4)EGO-1在减数分裂染色体配对中的作用。相关研究将调查其他自我基因。将对它们进行测试，以确定它们是否在RNA沉默中发挥作用；如果是，那么将启动分子研究。对EGO-3的分子研究将确定其基因产物的性质，以及它如何促进生殖系增殖。如果EGO-3在RNA沉默中不起作用，而其他EGO基因起作用，那么对EGO-3的分析将会减少工作

0077172MaineThe proposed studies investigate the regulation of cell fate during animal development. Experiments focus on how cell proliferation is regulated in germline tissue of the model organism, C. elegans. Germline proliferation in C. elegans is stimulated by a signal from cells in the somatic gonad. Germ cells that receive the signal will divide, whereas those that do not receive the signal will stop dividing and instead differentiate as sperm or eggs. This signaling occurs via a "Notch-type" biochemical pathway. Notch-type signaling pathways regulate development in diverse animal species; in mammals, they are implicated in certain cancers and other diseases. Many questions remain about the regulation of germline proliferation in C. elegans and how Notch-type signaling provokes a specific cellular response. For example, little is known about the targets of pathway activity or how pathway activity is regulated. Possible targets in the C. elegans germ line include genes that promote formation of gametes, such as gld-1 and gld-2. Notch-type signaling could promote proliferation by turning off gld-1 and gld-2 gene expression. To better understand how germline development is regulated, Dr. Maine and colleagues have identified and studied genes that interact genetically with a known component of the signaling pathway, glp-1. Here, Dr. Maine proposes to extend the analysis of several "ego" (enhancer of glp-1) genes. Previous studies from the Maine laboratory indicate that ego-1 gene activity is critical for both germline development and a poorly understood process called RNA silencing. RNA silencing is a means of gene regulation that has been observed in plants, animals, and fungi. It is thought to be a defense against viral infection, but the P.I. has data to suggest that it may also be an important regulatory mechanism during development. Consequently, she proposes to investigate potential target genes that might be regulated by RNA silencing during germline development, including gld-1 and gld-2. Several complementary studies will investigate (1) the expression of EGO-1 protein during germline development, (2) whether EGO-1 is essential for phenomena related to RNA silencing, (3) potential genetic interactions between ego-1 and other genes involved in RNA silencing, and (4) the role of EGO-1 in meiotic chromosomal pairing. Related studies will investigate other ego genes. They will be tested to determine if they function in RNA silencing; if so, then molecular studies will be initiated. Molecular studies of ego-3 will determine the nature of its gene product and how it functions to promote germline proliferation. Analysis of ego-3 will receive reduced effort if it does not function in RNA silencing while other Ego genes do so function