EXPLORING THE INTERACTION BETWEEN SGS1 AND TOP3

探索SGS1与TOP3之间的互动

• 批准号: 6721459
• 负责人: MARISA WAGNER
• 金额: $ 1.31万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6721459
• 关键词: DNA replication; DNA topoisomerases; cell cycle; chemical carcinogen; chemical carcinogenesis; chimeric proteins; chromatin; enzyme activity; genetic recombination; green fluorescent proteins; helicase; immunoprecipitation; mutagens; point mutation; recombinant proteins; tissue /cell culture

Human diseases that enhance cancer predisposition are associated with increased chromosome rearrangements. Yeast homologs have been found for a number of these disease genes and mutation of the yeast gene shown to cause hyper-recombination. Study of such yeast hyper- recombination mutants will lend insight to the disease processes and cancer etiology in general. The S. cerevisiae Sgs1 DNA helicase is highly homologous to the proteins which are mutated in the Wenner, Bloom and Rothmund-Thomson cancer predisposition syndromes. Sgs1 mutants were identified as suppressors of the slow growth of top3 DNA topoisomerase mutants. top3 mutants exhibit pleiotropic defects including hyper-recombination. The sgsl mutant phenotype is reminiscent of top3, albeit generally less severe. SGS1 epistasis to TOPS indicates that they function in the same pathway. In addition to Top3, yeast also contain the Top1 and Top2 topoisomerases. In pairwise combinations, the three topoisomerases exhibit synergistc defects indicating functional overlaps. Sgs1 physically interacts with Top2 and Top3. sgsl in combination with either topl or top2 mutation exhibits synergistic defects. The functional overlaps/antagonisms among Sgs1/Top3 and the other topoisomerases are not understood. The DNA substrates upon which Sgs1 and Top3 act in vivo are not known. Interestingly, Sgs1/Top3 interaction is conserved in humans. The knowledge of when and where Sgs1 and Top3 act during DNA replication/recombination in yeast can lend important insight to the human disease process and cancer etiology. The goal of this proposal is to investigate the functions of Sgs1 and Top3 in S. cerevisiae using combined genetic, biochemical, and cell biological approaches.

增强癌症易感性的人类疾病与染色体重排的增加有关。已经发现了许多这些疾病基因的酵母同源物，并且酵母基因的突变被证明会导致超重组。对此类酵母超重组突变体的研究将有助于了解疾病过程和一般癌症病因学。酿酒酵母 Sgs1 DNA 解旋酶与 Wenner、Bloom 和 Rothmund-Thomson 癌症易感综合征中突变的蛋白质高度同源。 Sgs1 突变体被鉴定为 top3 DNA 拓扑异构酶突变体缓慢生长的抑制因子。 top3 突变体表现出多效性缺陷，包括超重组。 sgsl 突变表型让人想起 top3，尽管通常不太严重。 SGS1 与 TOPS 的上位性表明它们在相同的途径中发挥作用。除 Top3 外，酵母还含有 Top1 和 Top2 拓扑异构酶。在成对组合中，三种拓扑异构酶表现出协同缺陷，表明功能重叠。 Sgs1 与 Top2 和 Top3 进行物理交互。 sgsl与top1或top2突变组合表现出协同缺陷。 Sgs1/Top3 和其他拓扑异构酶之间的功能重叠/拮抗作用尚不清楚。 Sgs1 和 Top3 在体内发挥作用的 DNA 底物尚不清楚。有趣的是，Sgs1/Top3 相互作用在人类中是保守的。了解 Sgs1 和 Top3 在酵母 DNA 复制/重组过程中何时何地发挥作用，可以为了解人类疾病过程和癌症病因学提供重要见解。本提案的目标是利用遗传、生化和细胞生物学相结合的方法研究 Sgs1 和 Top3 在酿酒酵母中的功能。