Control of DNA Replication and Cell Division

DNA 复制和细胞分裂的控制

• 批准号: 6687040
• 负责人: TERESA S WANG
• 金额: $ 37.52万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-05-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6687040
• 关键词: DNA directed DNA polymerase; DNA repair; DNA replication; Saccharomyces; cell cycle; cell growth regulation; fungal genetics; gene expression; gene mutation; phosphorylation; proliferating cell nuclear antigen

DESCRIPTION (provided by applicant): The overall goal of this research program is to investigate how eukaryotic cells respond to replication perturbations in order to maintain the genomic stability by using fission yeast as the model organism. When faced with chromosomal perturbations, eukaryotic organisms activate a complex set of signal transduction response pathways called checkpoints to regulate cell-cycle transition, to facilitate DNA repair or in some cases to induce apoptosis. Failure of these responses results in genomic instability, which can promote tumor development. In addition, cells have evolved other processes to deal with the genomic perturbations to restart replication. Cells can use a large repertoire of translesional DNA polymerases to perform either error-free or error-prone synthesis, which has the potential to generate point mutations and single base frameshifts. Cells can also use recombination/repair to restart replication, which has the potential of inducing deletion mutations in cells. Mutations in replication genes often induce a mutator phenotype characterized by deletion mutations and point mutations. Little is known about how checkpoints respond to the replication perturbations caused by replication mutants. Our recent studies have shown that mutations in checkpoint genes significantly affect the mutator phenotype in the replication mutants. These findings have led us to hypothesize: In response to genomic perturbation, the checkpoint-clamp recruits translesional polymerases onto chromatin for mutagenic synthesis which generates point mutations and recruits recombination/repair factor(s) to promote deletion mutations. In contrast, Cds1 kinase regulates the recombination/repair factors to prevent deletion mutations. Together these processes will facilitate recovery from a stalled replication to restart DNA replication. Specific Aims proposed to test this hypothesis are: (1). How do the checkpoint clamp and/or checkpoint-clamp-loader recruit translesional polymerases for mutagenic synthesis in order to restart a stalled replication fork? (2). How does the checkpoint effector kinase Cds1 function in preventing deletion mutations to occur, and does the checkpoint clamp/clamp-loader promote deletion mutations in cells to prevent replication fork from collapse and to restart a stalled replication fork?

描述（由申请人提供）： 本研究计划的总体目标是以裂殖酵母为模式生物，研究真核细胞对复制扰动的反应，以维持基因组的稳定性。当面临染色体扰动时，真核生物会激活一组称为检查点的复杂信号转导反应途径，以调节细胞周期转换，促进DNA修复或在某些情况下诱导细胞凋亡。这些反应的失败导致基因组不稳定，这可以促进肿瘤的发展。此外，细胞还进化出其他过程来处理基因组扰动，以重新启动复制。细胞可以使用大量的跨损伤DNA聚合酶来进行无错或易错的合成，这有可能产生点突变和单碱基移码。细胞还可以使用重组/修复来重新开始复制，这具有诱导细胞中缺失突变的潜力。复制基因的突变通常诱导以缺失突变和点突变为特征的增变子表型。关于检查点如何对复制突变体引起的复制扰动做出反应，人们知之甚少。我们最近的研究表明，在复制突变体中，检查点基因的突变显著影响增变子表型。这些发现使我们假设：为了响应基因组扰动，检查点钳将跨损伤聚合酶募集到染色质上用于诱变合成，其产生点突变并募集重组/修复因子以促进缺失突变。相反，Cds 1激酶调节重组/修复因子以防止缺失突变。这些过程将有助于从停滞的复制中恢复，以重新启动DNA复制。 为检验这一假设而提出的具体目标是： （一）.检查点钳和/或检查点钳加载器如何招募跨损伤聚合酶进行致突变合成，以重新启动停滞的复制叉？ （二）、检查点效应激酶Cds 1如何在防止缺失突变发生中起作用，检查点钳/钳加载器是否促进细胞中的缺失突变以防止复制叉崩溃并重新启动停滞的复制叉？