Suppression of translocations by RecQ-like DNA helicases

RecQ 样 DNA 解旋酶抑制易位

• 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
• 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

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.

项目摘要 某些具有极高癌症风险的人类遗传疾病，如布卢姆综合征 和沃纳综合征，与RecQ基因的DNA解旋酶突变有关。 家人酵母酿酒酵母的突变体缺乏Sgs 1，唯一的RecQ- 相关的DNA解旋酶，已被证明是一些优秀的模型系统 Bloom和Werner综合征的细胞表型，特别是关于 它们的超重组表型。虽然累积毛利率- 染色体重排在SGS 1中仅中度升高？变种人， 最近表明，缺乏Sgs 1的细胞特别容易经历复杂的， 高度分化基因中由小区域同源性驱动的重复易位 （60- 65%同一性）。尽管Sgs 1和错配修复蛋白是 相似但不相同（同源异型）序列之间的重组，只有Sgs 1是 抑制这些复杂和反复发生的易位所需的。的 该建议的目的是研究染色体内和染色体间的重组 在Sgs 1缺失的情况下引起同源性驱动的易位的机制。的 本研究的具体目的是：（1）确定基因结构和 染色体环境控制率和结构同源性驱动 SGS 1中的易位？缺乏DNA损伤检查点传感器或染色质的突变体 组装因素这将通过修改位置、方向和副本来实现 易位靶的数目以及同源块距离和DNA序列 身份(2)阐明DNA损伤检查点的差异要求 成分的抑制和形成反复易位在sgs 1？ 变种人(3)检查功能域的作用和已知的物理相互作用， sgs 1抑制同源异型驱动的易位。(4)确定的能力， 五种人RecQ样DNA解旋酶替代Sgs 1抑制 同源基因驱动的易位SGS 1将被人RecQ的cDNA取代 同源物，其中一些已在酵母中成功表达并抑制 《安全和稳定公约》的某些方面1？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， 揭示了导致大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。 这些研究将为DNA解旋的作用提供机制性的见解 酶在维持基因组完整性，并将阐明一般 导致染色体重排的机制，特别是基因易位， 其通常与人类癌症和染色体断裂综合征有关。