Genetic Architecture of Hsp90-buffered variation

Hsp90 缓冲变异的遗传结构

• 批准号: 6882032
• 负责人: Suzannah Rutherford
• 金额: $ 34.25万
• 依托单位: FRED HUTCHINSON CANCER RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6882032
• 关键词: Drosophilidae; computer data analysis; functional /structural genomics; gene environment interaction; gene expression; genetic mapping; genetic markers; genetic polymorphism; genotype; heat shock proteins; high performance liquid chromatography; molecular cloning; polymerase chain reaction; protein structure function; quantitative trait loci

DESCRIPTION (provided by applicant): Our present knowledge of the genes involved insusceptibilities to complex human diseases such as cancer is limited due to the large number of genetic and environmental factors involved and their complex interactions. Cancer is characterized by aberrant signaling through pathways required for regulated cell growth, death, or DNA maintenance. Single gene mutations in these pathways cause rare cancers, but common polymorphic alleles of unknown genes with modest effects on signaling are responsible for most cancers. To find these genes, human studies are difficult, costly, and biased toward previously known biological mechanisms and genes of large effect. An alternative approach is to find modifiers of conserved signaling pathways in model organismsand then study their human homologs variants associated with disease. The Hsp90 stress protein supports the activities of many conserved tumor suppressors, oncogenes, and cell cycle regulators. When Drosophila Hsp90 is limiting, polygenic variation with potent effects on development is expressed as strain specific abnormalities. We believe that the developmental novelties result from natural genetic variation affecting the strength of signaling through the developmental, regulatory, and growth control pathways determined by Hsp90 targets. Thus, a network of natural variation influencingHsp90-dependent signaling pathways in flies models the architecture of signaling variation for cancer predisposition in humans, and has the potential to drive the evolution of development. To identify natural Hsp90-buffered polymorphisms and place them in pathways we used laboratory selection for Hsp90-dependent eye abnormalities to generate replicate 'deformed eye' lines with a high fraction of affected flies. An inbred wild-type genetic background with normal eyes was crossed into the selection lines to construct over 1,400 recombinant isogenic mapping lines (clones). For each recombinant line, on average 50 flies having identical recombinant genotypes were scored for trait penetrance (probability affected) and saved for genotyping. Our specific aims are to 1) localize deformed eye polymorphisms by SQTL (Suppressor of Quantitative Trait Loci) and deletion mapping to test the idea that varied genetic architectures for deformed eye arose in the replicate lines. 2) Clone the wild-type alleles of deformed eye polymorphisms as suppressors of trait penetrance to determine whether hidden polymorphisms reside in Hsp90 targets or in peripheral genes of small effect. 3) Identify developmental processes and pathways responsible for the pathology of deformed eye to bring Hsp90-buffered variation into biological context. We expect this research will identify conserved Hsp90 target pathways and an extended network of naturally polymorphic genes that influence their function.

描述(由申请人提供)：由于涉及大量的遗传和环境因素及其复杂的相互作用，我们目前对涉及癌症等复杂人类疾病易感性的基因的了解有限。癌症的特征是通过调节细胞生长、死亡或DNA维持所需的通路发出异常信号。这些途径中的单基因突变会导致罕见的癌症，但对信号有轻微影响的未知基因的常见多态等位基因是大多数癌症的原因。要找到这些基因，人体研究是困难、昂贵的，而且偏向于先前已知的生物学机制和大效应基因。另一种方法是在模型生物中找到保守信号通路的修饰物，然后研究它们与疾病相关的人类同源变体。Hsp90应激蛋白支持许多保守的肿瘤抑制因子、癌基因和细胞周期调节因子的活性。当果蝇Hsp90处于极限状态时，对发育有潜在影响的多基因变异表现为品系特异性异常。我们认为，发育新颖性是由于自然遗传变异通过Hsp90靶标决定的发育、调节和生长控制途径影响信号强度。因此，在果蝇中影响Hsp90依赖的信号通路的自然变异网络模拟了人类癌症易感性的信号变异的结构，并有可能推动发育的进化。为了识别天然的Hsp90缓冲多态，并将它们置于路径中，我们使用实验室对依赖Hsp90的眼睛异常进行选择，以产生与高比例受影响的果蝇复制的“畸形眼睛”线。将近交系野生型遗传背景与正常眼杂交，构建了1400多个重组等基因作图系(克隆)。对于每个重组系，平均有50只具有相同重组基因的果蝇获得了性状外显率(受影响的概率)的评分，并保存下来用于基因分型。我们的具体目标是：1)通过SQTL(数量性状基因座抑制者)和缺失定位来定位变形眼的多态，以验证复制系中出现了变形眼的不同遗传结构的想法。2)克隆眼部畸形的野生型等位基因作为性状外显抑制因子，以确定Hsp90靶点或小效应外周基因是否存在隐性多态。3)确定导致眼睛畸形的发育过程和途径，以将Hsp90缓冲的变异纳入生物学背景。我们预计这项研究将确定保守的Hsp90靶通路和影响其功能的自然多态基因的扩展网络。