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：
7468137
负责人：
Kristina Schmidt
金额：
$ 26.46万
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 2013-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7468137
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 Individual Inherited Investigation Light Location Maintenance Malignant Neoplasms Mass Spectrum Analysis Measures Metabolic Pathway Mismatch Repair Mutate Mutation N-terminal Numbers PTPN22 gene Pathway interactions Phenotype Phosphorylation Phosphorylation Site Phosphotransferases Polymerase Chain Reaction Population Proteins Public Health RECQL gene Rad52 protein Range Rate Reporting Role Rothmund-Thomson syndrome Saccharomyces cerevisiae Site-Directed Mutagenesis Structure Syndrome Testing Thinking Time Topoisomerase Translocation Breakpoint Upper arm WRN gene Werner Syndrome Western Blotting Yeasts base cancer risk helicase homologous recombination in vivo inhibitor/antagonist insight man mutant novel promoter sensor tool yeast genetics yeast two hybrid system

项目摘要

DESCRIPTION (provided by applicant): 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 complexes 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. PUBLIC HEALTH RELEVANCE: The causes of genome instability, 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.

描述（由申请人提供）：某些具有极高癌症风险的人类遗传疾病，例如布卢姆综合征和维尔纳综合征，与 RecQ 家族 DNA 解旋酶的突变有关。缺乏 Sgs1（该酵母中唯一的 RecQ 相关 DNA 解旋酶）的酿酒酵母突变体已被证明是 Bloom 和 Werner 综合征某些细胞表型的优秀模型系统，特别是在其超重组表型方面。尽管在 sgs1 突变体中累积的总染色体重排率仅适度升高，但最近的研究表明，缺乏 Sgs1 的细胞特别容易发生复杂的、反复出现的易位，这种易位是由高度分化基因中的小同源区域（60-65% 同一性）驱动的。。尽管 Sgs1 和错配修复蛋白是相似但不相同（同源）序列之间重组的抑制剂，但抑制这些复合物和重复易位只需要 Sgs1。该提案的目的是研究在 Sgs1 缺失的情况下导致同源驱动易位的染色体内和染色体间重组机制。本研究的具体目的是：（1）确定基因结构和染色体环境在缺乏DNA损伤检查点传感器或染色质组装因子的sgs1突变体中控制同源驱动易位的速率和结构的程度。这将通过修改易位目标的位置、方向和拷贝数以及同源区块距离和 DNA 序列同一性来实现。 (2) 阐明 sgs1 突变体中 DNA 损伤检查点成分对于抑制和形成重复易位的差异要求。 (3) 检查 Sgs1 的功能域和已知的物理相互作用在抑制同源驱动易位中的作用。 (4) 确定五种人类 RecQ 样 DNA 解旋酶替代 Sgs1 抑制同源驱动易位的能力。 SGS1 将被人类 RecQ 同源物的 cDNA 取代，其中一些已在酵母中成功表达并抑制 sgs1 突变表型的某些方面。这些研究将为 RecQ 解旋酶在维持基因组完整性中的作用提供机制见解，并将揭示导致染色体重排的一般机制，特别是通常与人类癌症相关的基因易位。公共卫生相关性：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解旋酶在维持基因组完整性中的作用提供机制见解，并将阐明导致染色体重排的一般机制，特别是基因易位，这通常与人类癌症和染色体断裂综合征有关。