Suppression of translocations by RecQ-like DNA helicases

RecQ 样 DNA 解旋酶抑制易位

基本信息

批准号：
8269737
负责人：
Kristina Schmidt
金额：
$ 27.33万
依托单位：
UNIVERSITY OF SOUTH FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-01 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8269737
关键词：
Affect Aging Alleles BLM gene Bacteria Biological Models Bloom Syndrome Cells Chromatin Modeling Chromosomal Breaks Chromosomal Rearrangement Chromosome Breakage Chromosome Structures Chromosomes Chromosomes, Human, Pair 14 Chromosomes, Human, Pair 5 Collection Complementary DNA Complex Controlled Environment DNA DNA Repair DNA Sequence DNA Sequence Rearrangement DNA damage checkpoint DNA repair protein Disease Dominant-Negative Mutation Environment Family Frequencies Gene Structure Genes Genetic Genetic Polymorphism Genetic Recombination Genome Genomic Instability Goals Growth Hereditary Disease Homologous Gene Human Human Genetics Individual Inherited Investigation Light Location Maintenance Malignant Neoplasms Mass Spectrum Analysis Measures Metabolic Pathway Mismatch Repair Mutate Mutation N-terminal Pathway interactions Phenotype Phosphorylation Phosphorylation Site Phosphotransferases Population Proteins RECQL gene Rad52 protein Reporting Role Rothmund-Thomson syndrome Saccharomyces cerevisiae Site-Directed Mutagenesis Structure Syndrome Testing Time Topoisomerase Translocation Breakpoint WRN gene Werner Syndrome Western Blotting Yeasts arm base cancer risk helicase homologous recombination human DNA in vivo inhibitor/antagonist insight man mutant novel promoter sensor tool yeast genetics yeast two hybrid system

项目摘要

Project Summary Certain human genetic disorders with extreme cancer risk, such as Bloom's syndrome and Werner syndrome, are associated with mutations in DNA helicases of the RecQ family. Mutants of the yeast Saccharomyces cerevisiae that lack Sgs1, the only RecQ- related DNA helicase in this yeast, have proven to be excellent model systems for some cellular phenotypes of the Bloom's and Werner syndromes, especially with respect to their hyperrecombination phenotype. Although rates of accumulating gross- chromosomal rearrangements are only moderately elevated in sgs1? mutants, it was recently shown that cells lacking Sgs1 are uniquely susceptible to undergoing complex, recurring translocations driven by small regions of homology in highly diverged genes (60-65 % identity). Although Sgs1 and mismatch repair proteins are inhibitors of recombination between similar but nonidentical (homeologous) sequences, only Sgs1 is required for the suppression of these complex and recurring translocations. The objective of this proposal is to study the intra- and interchromosomal recombination mechanisms that cause homeology-driven translocations in the absence of Sgs1. The specific aims of this study are to: (1) Determine the extent to which gene structure and chromosome environment control the rate and structure of homeology-driven translocations in sgs1? mutants lacking DNA damage checkpoint sensors or chromatin assembly factors. This will be achieved by modifying location, orientation and copy number of translocation targets as well as homology block distance and DNA sequence identity. (2) Elucidate the differential requirement of DNA-damage checkpoint components for the suppression and formation of recurring translocations in sgs1? mutants. (3) Examine the role of functional domains and known physical interactions of Sgs1 in the inhibition of homeology-driven translocations. (4) Determine the ability of the five human RecQ-like DNA helicases to substitute for Sgs1 in the suppression of homeology-driven translocations. SGS1 will be replaced with cDNAs of human RecQ homologs, some of which have been successfully expressed in yeast and suppress some aspects of the sgs1? mutant phenotype. These studies will provide mechanistic insights into the role of RecQ helicases in the maintenance of genome integrity and will shed light on the general mechanisms leading to gross-chromosomal rearrangements, especially gene translocations, which are often associated with human cancers. Project Narrative The causes of genome instablity, which is a hallmark of most cancers, are still unclear. The proposed studies will provide mechanistic insights into the role of DNA unwinding enzymes in the maintenance of genome integrity and will shed light on the general mechanisms leading to chromosomal rearrangements, especially gene translocations, which are often associated with human cancers and chromosome breakage syndromes.

项目概要某些具有极高癌症风险的人类遗传疾病，例如布卢姆综合症和 Werner 综合征，与 RecQ 的 DNA 解旋酶突变有关家庭。缺乏 Sgs1（唯一的 RecQ-）的酿酒酵母突变体这种酵母中相关的 DNA 解旋酶已被证明是某些优秀的模型系统布鲁姆综合征和维尔纳综合征的细胞表型，特别是关于他们的超重组表型。尽管累计毛利率 sgs1 中染色体重排仅中度升高？突变体，原来是最近表明，缺乏 Sgs1 的细胞特别容易经历复杂的、由高度分化基因中的小同源区域驱动的重复易位（60-65% 同一性）。尽管 Sgs1 和错配修复蛋白是相似但不相同（同源）序列之间的重组，只有 Sgs1 是抑制这些复杂且反复出现的易位是必需的。这该提案的目的是研究染色体内和染色体间重组在缺乏 Sgs1 的情况下导致同源驱动易位的机制。这本研究的具体目的是：（1）确定基因结构和染色体环境控制同源驱动的速率和结构 sgs1 中的易位？缺乏 DNA 损伤检查点传感器或染色质的突变体装配因素。这将通过修改位置、方向和副本来实现易位目标的数量以及同源块距离和 DNA 序列身份。 (2) 阐明DNA损伤检查点的差异要求 sgs1 中抑制和形成重复易位的成分？突变体。 (3) 检查功能域的作用和已知的物理相互作用 Sgs1 抑制同源驱动的易位。 (4) 确定人员的能力五种人类 RecQ 样 DNA 解旋酶替代 Sgs1 抑制同源驱动的易位。 SGS1 将被人类 RecQ 的 cDNA 取代同系物，其中一些已在酵母中成功表达并抑制 sgs1 的某些方面？突变表型。这些研究将提供机制深入了解 RecQ 解旋酶在维持基因组完整性中的作用，并将阐明导致染色体重排的一般机制，尤其是基因易位，通常与人类癌症有关。项目叙述基因组不稳定是大多数癌症的标志，其原因仍不清楚。拟议的研究将为 DNA 解旋作用提供机制见解酶在维持基因组完整性中的作用，并将揭示一般导致染色体重排，特别是基因易位的机制，这通常与人类癌症和染色体断裂综合症有关。