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：
7846143
负责人：
Kristina Schmidt
金额：
$ 26.2万
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/7846143
关键词：
Affect Age 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 PTPN22 gene 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 Werner Syndrome Western Blotting Yeasts arm base cancer risk helicase homologous recombination human DNA in vivo inhibitor/antagonist insight man mutant novel promoter public health relevance 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）：某些具有极端癌症风险的人遗传疾病，例如Bloom综合征和Werner综合征，与RECQ家族的DNA解旋酶突变有关。缺乏SGS1的酵母菌酿酒酵母的突变体是该酵母中唯一相关的DNA解旋酶，已被证明是Bloom和Werner综合征的某些细胞表型的出色模型系统，尤其是在其过度混合表型方面。尽管累积的总染色体重排的速率仅在SGS1突变体中适度升高，但最近显示，缺乏SGS1的细胞对经历了复杂的复杂，经常出现的易位，由高度分歧的基因中的同源性小区域驱动（60-65％的身份）。尽管SGS1和不匹配修复蛋白是相似但非相同（同源）序列之间重组的抑制剂，但仅需要SGS1才能抑制这些复合物和经常性的易位。该提案的目的是研究在没有SGS1的情况下引起主词驱动易位的染色体内和染色体内重组机制。这项研究的具体目的是：（1）确定基因结构和染色体环境控制缺乏DNA损伤检查点传感器或染色质组装因子的SGS1突变体中主体驱动的易位的速率和结构的程度。这将通过修改位置，易位目标的方向和拷贝数以及同源性块距离和DNA序列身份来实现。（2）阐明了DNA破坏检查点成分的差异需求，以抑制和形成SGS1突变体中的重复易位。（3）检查功能领域的作用和SGS1的已知物理相互作用在抑制主体驱动的易位中的作用。（4）确定五个人类RECQ样DNA解旋酶在抑制主体驱动的易位时用SGS1代替SGS1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了SGS1突变体表型的某些方面。这些研究将提供有关RECQ解旋酶在维持基因组完整性中的作用的机理见解，并将阐明导致总染色体重排的一般机制，尤其是基因易位，尤其是与人类癌症有关的基因易位。公共卫生相关性：大多数癌症的标志基因组不稳定性的原因仍然不清楚。拟议的研究将提供机械洞察力，以了解DNA释放酶在维持基因组完整性中的作用，并阐明导致染色体重排的一般机制，尤其是基因易位，尤其是与人类癌症和染色体破裂综合症有关的基因易位。