Genes that influence LIN-12/Notch activity in C. elegans

描述（由研究者提供）：LIN-12/Notch蛋白是介导细胞间相互作用的受体，在动物发育过程中指定细胞命运。Notch活性在哺乳动物发育的许多细胞命运决定中起着突出作用。在成年期，Notch活性继续在更新人群中发挥重要作用，包括干细胞、免疫系统和上皮细胞。在人类患者和小鼠模型中，LIN-12/Notch蛋白的异常、组成性激活导致某些癌症；在其他情况下，LIN-12/Notch活性可以作为肿瘤抑制因子发挥作用。线虫中LIN-12/Notch信号的研究已经并将继续与理解正常哺乳动物发育和严重人类疾病的分子机制直接相关。本研究旨在通过强大的遗传方法鉴定和表征线虫中影响LIN-12/Notch信号的基因。遗传学研究可以识别和阐明影响LIN-12/Notch信号的因素的作用，并可以为癌症治疗提供新的方法。例如，最初被描述为激活秀丽隐杆线虫LIN-12/Notch的相同类型的点突变随后被发现可引起T急性淋巴细胞白血病（T- all）。早老素/ γ -分泌酶最初通过抑制LIN-12的活化点突变与LIN-12/Notch信号通路相关，现在是临床试验中对抗T-ALL的治疗靶点。然而，对这种治疗的耐药性与肿瘤抑制因子SEL- 10/Fbw7的突变有关，SEL- 10/Fbw7最初在秀丽隐杆线虫中作为lin-12活性的负调节因子被分离出来。与早老素一样，活化的LIN-12/Notch的新抑制因子可能识别出新的阳性因子，有可能作为治疗靶点；如SEL-10/Fbw7，新的负面因素可能阐明使肿瘤对治疗剂产生耐药性的过程。针对这些目标，我们提出了四个具体目标。首先，通过筛选活化的lin-12/Notch蛋白的抑制因子，对lin-12/Notch活性的新候选阳性调节因子进行表征。其次，从分子上识别一个基因，self -4，在类似的传统基因筛选中被识别出来。第三，寻找新的LIN-12靶基因，因为过去的分析表明，一些LIN-12靶基因调节LIN-12的活性并与其他途径进行串扰。第四，表征在RNAi筛选中获得的新的候选负调节因子，并探索RNAi与lin-12活性调节之间的潜在联系。公共卫生相关性：LIN-12/Notch蛋白是介导细胞间相互作用的受体，在动物发育过程中指定细胞命运。Notch活性在哺乳动物发育的许多细胞命运决定中起着重要作用，LIN- 12/Notch蛋白的异常组成性激活导致某些癌症。本提案的重点是鉴定和表征影响LIN-12/Notch信号的基因，利用秀丽隐杆线虫中可用的强大遗传方法。

DESCRIPTION (provided by investigator): LIN-12/Notch proteins are receptors that mediate cell-cell interactions that specify cell fate during animal development. Notch activity plays a prominent role in many cell fate decisions in mammalian development. During adulthood, Notch activity continues to play important roles in renewing populations, including stem cells, the immune system, and epithelial cells. Aberrant, constitutive activation of LIN-12/Notch proteins causes certain cancers in human patients and in murine models; in other contexts, LIN-12/Notch activity can function as a tumor suppressor. Studies of LIN-12/Notch signaling in C. elegans have been, and continue to be, directly relevant to understanding the molecular mechanisms underlying normal mammalian development and serious human diseases. This proposal is concerned with identifying and characterizing genes that influence LIN-12/Notch signaling through powerful genetic methods in C. elegans. Genetic studies can identify and illuminate the roles of factors that influence LIN-12/Notch signaling and can inform new approaches to cancer treatment. For example, the same kinds of point mutations first described as activating C. elegans LIN-12/Notch were subsequently found to cause T acute lymphoblastic leukemia (T-ALL). Presenilin/gamma-secretase, first linked to LIN-12/Notch signaling through suppressors of activating point mutations in lin-12, is now a therapeutic target in clinical trials for combating T-ALL. Resistance to this therapy, however, has been linked to mutations in a tumor suppressor, SEL- 10/Fbw7, first isolated as a negative regulator of lin-12 activity in C. elegans. Like presenilin, new suppressors of activated LIN-12/Notch may identify new positive factors with the potential to serve as therapeutic targets; like SEL-10/Fbw7, new negative factors may illuminate processes that make tumors resistant to therapeutic agents. We propose four specific aims with these goals. First, to characterize new candidate positive regulators of lin-12/Notch activity obtained through an RNAi screen for suppressors of an activated LIN-12/Notch protein. Second, to identify molecularly a gene, sel-4, identified in a similar conventional genetic screen. Third, to identify new LIN-12 target genes, as past analysis indicates some LIN-12 target genes modulate lin-12 activity and cross-talk with other pathways. Fourth, to characterize new candidate negative regulators obtained in an RNAi screen and to explore a potential connection between RNAi and regulation of lin-12 activity. PUBLIC HEALTH RELEVANCE: LIN-12/Notch proteins are receptors that mediate cell-cell interactions that specify cell fate during animal development. Notch activity plays a prominent role in many cell fate decisions in mammalian development, and aberrant, constitutive activation of LIN- 12/Notch proteins causes certain cancers. This proposal is focused on identifying and characterizing genes that influence LIN-12/Notch signaling, exploiting the powerful genetic methods available in C. elegans.