Sources and consequences of phenotypic variation in complex regulatory networks

复杂调控网络中表型变异的来源和后果

基本信息

批准号：
7887887
负责人：
Mark L Siegal
金额：
$ 22.85万
依托单位：
NEW YORK UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-04-02 至 2014-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7887887
关键词：
Adaptive Behaviors Affect Alleles Animal Model Antineoplastic Agents Architecture Biological Assay Biomedical Research Buffers Categories Cell Cycle Cell physiology Cells Cellular Morphology Characteristics Chromosomal Instability Chromosome Segregation Chromosome Structures Clinical Clinical Trials Collection Complement Complex Computer Simulation DNA Binding Defect Deletion Mutation Dependence Development Diagnosis Disease Disease Outcome Dissent Engineering Environment Epigenetic Process Essential Genes Evolution Exhibits Failure Foundations Frequencies Future Gene Deletion Gene Expression Generations Genes Genetic Genetic Variation Genome Genome Stability Genomic Instability Genotype Goals Growth Haploidy Heterogeneity Histones Individual Individual Differences Knock-out Knowledge Laboratories Lead Link Malignant Neoplasms Maps Measures Mediator of activation protein Messenger RNA Methods Modeling Molecular Mutation Organism Phenotype Population Prevention Process Property Proteins Regulator Genes Relative (related person)Role SAGA Saccharomyces cerevisiae Sample Size Shapes Site Source Structure System Testing Time Transcriptional Regulation Translating Untranslated Regions Variant Work Yeasts base human disease improved insight loss of function mutation member mutant neoplastic cell novel prevent protein protein interaction public health relevance research study segregation trait transcription factor tumor progression

项目摘要

DESCRIPTION (provided by applicant): The molecular systems underlying complex traits are in general poorly understood. Even less well understood is how genetic and environmental differences between individuals translate into phenotypic differences. A general feature of this mapping from genotype to phenotype is robustness, or the buffering of the phenotype against genetic and environmental variation. Complex human diseases can be viewed as failures of robust systems, with phenotypic variation manifesting as individual differences in clinical presentation and in disease outcome. Phenotypic variation is a product of and provides a window into the evolutionary processes that have shaped regulatory networks. The long-term goal of this project is to understand at a mechanistic level the sources and the consequences of variation in complex phenotypes. Specifically, this project will study variation in single-cell morphology of the yeast Saccharomyces cerevisiae in different genetic backgrounds. Yeast is an established model organism for understanding basic cellular processes, and also an important model for human disease, particularly the cell-cycle defects and chromosome instability (CIN) associated with cancer. Specific Aim 1 is to determine the congruence between mechanisms that buffer complex phenotypes against environmental variation and against genetic variation. Previous experiments identified hundreds of deletion mutations that increase morphological variation in isogenic cells. This disrupted buffering of environmental differences will be compared to that of genetic differences by introducing a subset of these mutations into diverse yeast strains. Because of the importance of transcriptional networks in robustness, particular focus will be on mutations in genes that encode transcriptional regulators. Genes that act in chromosome organization are also disproportionately found to be required for buffering. One such gene, HTZ1, encodes H2A.Z, a histone variant that is required for proper transcriptional regulation and also proper chromosome segregation. Specific Aim 2 is to determine the relative contributions to phenotypic variation of impaired buffering and CIN, using engineered mutations in HTZ1 that separate these two sources of variation. Whereas the genetic variability that accompanies CIN in cancer has been a long-recognized potential source of phenotypic heterogeneity, impaired buffering of regulatory networks has not been. Specific Aim 3 is to test whether partial loss-of-function mutations in essential genes impair buffering. Nonessential genes that contribute to robustness share properties with essential genes, such as participation in core cellular processes and high connectivity in genetic networks. This observation raises the possibility that essential genes are major contributors to robustness. A comprehensive collection of strains containing hypomorphic mutations in essential genes will be used to determine the extent to which these genes buffer morphological phenotypes. The project will test key hypotheses about the genetic architecture of robustness and may reveal an underappreciated mechanism generating heterogeneity in human disease. PUBLIC HEALTH RELEVANCE: Complex human diseases, such as cancer, are affected by a large number of environmental and genetic factors, making them difficult to diagnose, treat and prevent. We will use laboratory experiments to understand how variation in these factors produces variability in complex traits. This will advance our understanding of the molecular mechanisms underlying healthy and diseased states.

描述（由申请人提供）：一般来说，人们对复杂性状背后的分子系统了解甚少。更不为人所知的是个体之间的遗传和环境差异如何转化为表型差异。这种从基因型到表型的映射的一般特征是鲁棒性，或者表型对遗传和环境变化的缓冲。复杂的人类疾病可以被视为强大系统的失败，表型变异表现为临床表现和疾病结果的个体差异。表型变异是形成调节网络的进化过程的产物，并提供了了解该过程的窗口。该项目的长期目标是在机械层面上了解复杂表型变异的来源和后果。具体来说，该项目将研究不同遗传背景下酿酒酵母单细胞形态的变化。酵母是了解基本细胞过程的既定模型生物，也是人类疾病的重要模型，特别是与癌症相关的细胞周期缺陷和染色体不稳定性（CIN）。具体目标 1 是确定针对环境变异和遗传变异缓冲复杂表型的机制之间的一致性。之前的实验发现了数百个缺失突变，这些突变增加了同基因细胞的形态变异。通过将这些突变的子集引入不同的酵母菌株中，可以将环境差异的缓冲破坏与遗传差异的缓冲进行比较。由于转录网络在鲁棒性方面的重要性，我们将特别关注编码转录调节因子的基因突变。还发现在染色体组织中起作用的基因不成比例地需要缓冲。其中一个基因 HTZ1 编码 H2A.Z，这是一种组蛋白变体，是正确转录调控和正确染色体分离所必需的。具体目标 2 是利用 HTZ1 中的工程突变来区分这两种变异来源，从而确定缓冲受损和 CIN 对表型变异的相对贡献。尽管癌症中伴随 CIN 的遗传变异长期以来一直被认为是表型异质性的潜在来源，但监管网络的缓冲受损却并非如此。具体目标 3 是测试必需基因的部分功能丧失突变是否会损害缓冲。有助于稳健性的非必需基因与必需基因具有相同的特性，例如参与核心细胞过程和遗传网络的高连接性。这一观察结果提出了一种可能性，即必需基因是稳健性的主要贡献者。包含必需基因亚型突变的菌株的全面收集将用于确定这些基因缓冲形态表型的程度。该项目将测试有关稳健性遗传结构的关键假设，并可能揭示人类疾病中产生异质性的未被充分认识的机制。公共卫生相关性：癌症等复杂的人类疾病受到大量环境和遗传因素的影响，使其难以诊断、治疗和预防。我们将使用实验室实验来了解这些因素的变化如何产生复杂性状的变化。这将增进我们对健康和疾病状态下分子机制的理解。