Factors Controlling Minisatellite Stability in Yeast

控制酵母小卫星稳定性的因素

• 批准号: 7094065
• 负责人: David T. Kirkpatrick
• 金额: $ 24.71万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7094065
• 关键词: DNA repair; Saccharomyces cerevisiae; cancer risk; chemical stability; fungal genetics; gene expression; gene mutation; gene rearrangement; genetic recombination; genetic regulation; genetic screening; human data; meiosis; nucleic acid sequence; polymerase chain reaction; transcription factor

DESCRIPTION (provided by applicant): Maintenance of genome stability is of paramount importance; genome instability has been correlated with numerous disease states in humans, for example. Repetitive DNA is often the source of genomic rearrangements. One class of repetitive DNA, minisatellite sequences, have an approximate repeat unit length ranging from 15 to 100 nucleotides. Mammalian genomes contain a large number of different minisatellite tracts. While these tracts are stable during the mitotic cell cycle, they destabilize during meiosis, altering in both length and sequence composition. Unfortunately the genetic and physical factors controlling the stability of minisatellite tracts are unknown. Minisatellite tracts can have genetic functions; a human minisatellite tract associated with the HRAS1 oncogene acts as a transcription enhancer for HRAS1, and altered minisatellite alleles have been correlated with HRAS1 oncogenesis. We established a model system by introducing the HRAS1 minisatellite into the HIS4 locus in the yeast S. cerevisiae, where it exhibits all of the phenotypes observed in mammalian cells. The tract stimulates transcription and meiotic recombination, and undergoes meiosis-specific alterations in length. Removal of a recombination-initiating endonuclease eliminates tract alterations, while removal of a meiotic DNA loop repair pathway specifically reduces the frequency of tract expansions. These initial studies will be extended by determining the complete complement of genes governing stability of the HRAS1 minisatellite. Two general screens for minisatellite stability maintenance genes have been initiated, in addition to a directed screen of the Yeast Deletion Strain Bank. The screens will identify genes required for minisatellite stability as well as genes affecting DNA loop repair. Finally, we will determine the basis for an observed correlation between HRAS1 minisatellite allele state and breast cancer oncogenesis, through genetic analysis of native human HRAS1 minisatellite alleles. Many of 1he proposed experiments cannot be done in a mammalian system; the HIS4-HRAS1 minisatellite system is the only means to gain these important data. These studies will provide insights into genome maintenance, recombination, DNA repair, transcription initiation, and aspects of cancer predisposition.

描述（由申请人提供）：维持基因组稳定性至关重要；例如，基因组不稳定性与人类的许多疾病状态有关。重复DNA通常是基因组重排的根源。一类重复 DNA（小卫星序列）的重复单位长度约为 15 至 100 个核苷酸。哺乳动物基因组包含大量不同的小卫星束。虽然这些束在有丝分裂细胞周期中是稳定的，但它们在减数分裂过程中不稳定，长度和序列组成都发生变化。不幸的是，控制小卫星束稳定性的遗传和物理因素尚不清楚。小卫星束可以具有遗传功能；与 HRAS1 癌基因相关的人类小卫星束充当 HRAS1 的转录增强子，并且改变的小卫星等位基因与 HRAS1 肿瘤发生相关。 我们通过将 HRAS1 小卫星引入酿酒酵母的 HIS4 位点建立了一个模型系统，它表现出在哺乳动物细胞中观察到的所有表型。该束刺激转录和减数分裂重组，并经历减数分裂特异性的长度改变。去除重组起始核酸内切酶可消除束改变，而去除减数分裂 DNA 环修复途径可特异性降低束扩张的频率。 这些初步研究将通过确定控制 HRAS1 小卫星稳定性的完整基因来扩展。除了酵母删除菌株库的定向筛选之外，还启动了两项小卫星稳定性维持基因的常规筛选。筛选将识别小卫星稳定性所需的基因以及影响 DNA 环修复的基因。最后，我们将通过对天然人类 HRAS1 小卫星等位基因的遗传分析，确定 HRAS1 小卫星等位基因状态与乳腺癌肿瘤发生之间观察到的相关性的基础。 1他提出的许多实验无法在哺乳动物系统中进行； HIS4-HRAS1小型卫星系统是获取这些重要数据的唯一手段。这些研究将为基因组维护、重组、DNA 修复、转录起始和癌症易感性等方面提供深入见解。