(PQ1) The role of cell-to-cell variation in the penetrance of heritable mutant RAS hypodermal neoplasias

项目概述：我们的目标是提供问题的答案：“什么分子 遗传癌症易感性的个体中影响疾病易感性的机制 基因？我们计划从遗传学和细胞生物学的角度来回答这个问题。更具体地说， 我们计划确定哪些基因影响RAS驱动的肿瘤的发病率，然后 观察这些基因如何改变基因表达和细胞分裂的定型程序， 用定量光学显微镜直接观察基因表达和细胞分裂。 患有努南综合征或科斯特洛综合征的儿童出生时就有RAS突变， 常见癌基因有些人，但不是所有的人都患上癌症。RAS驱动的癌症 目前的抗HSP 90临床试验显示出一些希望，但 毒品是有毒的。我们有证据表明，其他伴侣可能是合适的目标， 抑制基于Ras的癌症形成。我们有证据表明 影响Ras驱动的瘤形成外显率的是表观遗传的表达能力 每单位基因含有更多或维持更多生物活性的蛋白质分子。 在本研究中，我们将研究等基因C。具有Ras增益功能的线虫 导致不完全渗透性皮下瘤形成的等位基因。当这些动物继承了 在他们唯一的Ras同源物let-60中获得功能突变，就像努南的孩子一样 综合征，他们中的一些人会发展成肿瘤。大约90%携带Ras癌基因的蠕虫 将获得1-4个皮下肿瘤在发展过程中，在应对保守的，癌症- EGF、Notch和WNT信号通路。在携带野生型Ras的蠕虫中， 会控制外阴的器官形成肿瘤的最初表现 可靠地发生，在同一时间，在发展过程中，一次又一次的权利，当信号 外阴的发育我们有一个系统，在这个系统中， 这样我们就可以确切地看到细胞中发生了什么，这些细胞可能会或可能不会成为肿瘤。 我们将进行反向遗传筛查，以确定影响瘤形成的基因。我们将观察 这些基因如何改变一系列正常协调的基因表达事件， 通过测量基因表达引起细胞增殖并改变细胞命运， 活细胞 我们具体的中心假设是，确实发生肿瘤的动物具有表观遗传 导致翻译效率增加的伴侣蛋白表达差异，导致 Ras功能等位基因获得的有效基因剂量越高， 肿瘤的表现。我们提供了强有力的证据，这一假设的方法。

Project Summary: Our goal is to provide answers to the question: “What molecular mechanisms influence disease penetrance in individuals who inherit a cancer susceptibility gene?”. We plan to answer this question in terms of genetics and cell biology. More specifically, we plan to identify which genes influence the penetrance of RAS-driven neoplasia, and then observe how these genes alter the stereotyped program of gene expression and cell division by directly observing gene expression and cell division with quantitative light microscopy. Children with Noonan or Costello syndromes are born with mutations in RAS, the most common oncogene. Some, but not all of these individuals develop cancer. RAS-driven cancers are notoriously difficult to treat. Current anti-HSP90 clinical trials show some promise, but the drugs are toxic. We have evidence that other chaperones may be suitable targets for suppressing Ras-based cancer formation. We have evidence that the molecular mechanism that influences Ras-driven neoplasia penetrance is the epigenetically heritable ability to express more or maintain more biologically active molecules of protein per unit gene. In the proposed research, we will study isogenic C. elegans with a Ras gain of function allele that results in incompletely penetrant hypodermal neoplasia. When these animals inherit a gain of function mutation in their sole Ras homolog, let-60, just like children with Noonan syndrome, some of them will develop neoplasias. About 90% of Ras oncogene bearing worms will acquire 1-4 hypodermal neoplasias during development, in response to conserved, cancer- related EGF, Notch and WNT signaling pathways. In worms with wild-type Ras, these pathways would normally control organogenesis of the vulva. The initial manifestation of neoplasia happens reliably, at the same time during development, over and over – right when the signal for vulva development happens. We have a system wherein we know exactly where and when to look, so we can see exactly what happens in cells that may or may not become neoplastic. We will perform a reverse genetic screen to identify genes that affect neoplasia. We will watch how these genes change the series of normally well-coordinated gene expression events that cause cell proliferation and transform cell fate by measuring gene expression while it happens in living cells. Our specific central hypothesis is that animals that do develop neoplasias have epigenetic differences in chaperone expression that cause an increase in translation efficiency, resulting in a higher effective gene dosage of the Ras gain of function allele, and that in turn, results in the manifestation of neoplasia. We provide strong evidence for this hypothesis in the approach.