Biochemistry and Function of C. elegans RNA helicase A

描述(申请人提供)：生物体由生殖细胞在复杂的细胞机制控制下以精确的组织模式发育而成。这些机制中的许多在高等真核生物中都是保守的。生殖细胞是一种干细胞，它具有独特的分裂能力，可以产生更多的干细胞，或者分裂和分化成一个完整的有机体。干细胞维持的调控机制还不是很清楚，它们之所以重要，是因为干细胞具有治疗帕金森氏症等人类疾病的潜力。这个项目涉及对模式生物--线虫线虫--的干细胞增殖调控的研究。这些动物有一个含有干细胞的性腺，该项目的重点是确定一种控制这些细胞增殖的特定蛋白质的功能，该蛋白质称为RNA解旋酶A(RHA-1)。解旋酶利用ATP水解产生的能量将双链核酸分离成单链，而RNA解旋酶参与转录和剪接等信使核糖核酸代谢的各个步骤。RNA解旋酶A对于小鼠、苍蝇和模式生物秀丽线虫的正常发育是必不可少的。到目前为止进行的实验表明，RHA-1是生殖细胞增殖所必需的，但RHA-1控制增殖的机制尚不清楚。RHA-1基因大片段缺失的虫体的表型与其他生殖系缺陷突变虫体的表型比较表明，RHA-1可能通过控制转录或参与胚系中的信号通路发挥作用。在这项建议中，提出了遗传和分子生物学实验，以测试RHA-1是否具有这些功能之一或不同的功能。RHA-1的生化活性尚未确定，这些活性可能是其在生殖系增殖中所必需的。因此，描述了确定RHA-1正常工作所需的生化活性的实验。生殖系中细胞分裂的调节也与癌症治疗有关，因为许多控制细胞分裂的过程是保守的，这些过程在癌细胞中被破坏。该项目的最终目标是确定转录和其他细胞过程如何影响包括人类在内的所有真核生物的发育。

DESCRIPTION (provided by applicant): Organisms develop from reproductive cells in precisely organized patterns that are controlled by complex cellular mechanisms. Many of these mechanisms are conserved throughout higher eukaryotes. Reproductive cells are a type of stem cell that has the unique ability to divide to produce more stem cells or to divide and differentiate into a complete organism. The mechanisms regulating stem cell maintenance are not well understood, and they are important because stem cells have the potential to treat human diseases such as Parkinson's disease. This project involves a study of the regulation of stem cell proliferation in a model organism, the nematode C. elegans. These animals have a gonad containing stem cells, and the focus of this project is to determine the function of a specific protein controlling proliferation of these cells called RNA Helicase A (RHA-1). Helicases use energy from ATP hydrolysis to separate duplex nucleic acids into single strands, and RNA helicases are involved in various steps of mRNA metabolism, such as transcription and splicing. RNA helicase A is essential for proper development in mice, flies, and the model organism C. elegans. Experiments performed thus far demonstrate that RHA-1 is required for germline proliferation, but the mechanism by which RHA-1 controls proliferation is not known. A comparison of the phenotype of worms containing a large deletion in the rha-1 gene with the phenotype of other mutant worms with germline defects suggests that RHA-1 may act by controlling transcription or by participating in a signaling pathway in the germline. In this proposal, genetic and molecular biology experiments are presented to test whether RHA-1 has one of these functions or a different function. The biochemical activities of RHA-1 have not been determined, and these activities are presumably required for its role in germline proliferation. Thus, experiments are described to determine the biochemical activities of RHA-1 that are required for it to work properly. The regulation of cell division in the germline is also related to cancer treatment, since many processes controlling cell division are conserved, and these processes become disrupted in cancerous cells. The ultimate goal of this project is to determine how transcription and other cellular processes affect development in all eukaryotes, including humans.