Molecular analyses of RECQ1 functions in genome maintenance

RECQ1 在基因组维护中的功能的分子分析

• 批准号: 8232579
• 负责人: Sudha Sharma
• 金额: $ 28.91万
• 依托单位: HOWARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8232579
• 关键词: Molecular; analyses; RECQ1; functions; genome

DESCRIPTION (provided by applicant): The RecQ helicase family is a group of highly conserved DNA unwinding enzymes critical in guarding genome stability in all kingdoms of life. Human RecQ homologs include RECQ1, BLM, WRN, RECQL4, and RECQ5. Although the five human RecQ proteins are similar in their catalytic core and share certain biochemical properties in vitro, they are clearly not redundant. Mutations in BLM, WRN and RecQ4 are associated with distinct genetic disorders of Bloom, Werner, and Rothmund-Thomson syndromes, respectively. Thus, a defect in one RecQ protein is sufficient to cause genomic instability that cannot be compensated by other RecQ homologs. However, what makes each RecQ protein unique is not understood. Dissecting the functions of each human RecQ helicase, and comparing the similarities and differences among them, will reveal which aspects of RecQ functions in DNA metabolism are essential for genome maintenance. The goal of this proposal is to examine molecular functions of RECQ1, the most abundant but least characterized human RecQ helicase homolog. Recently, we have shown that RECQ1 is essential for genome stability maintenance; its deficiency induces accumulation of DNA damage and chromosomal instability. RECQ1 binds and unwinds DNA structures that represent intermediates of DNA recombination repair, and interacts physically and functionally with proteins involved in regulating genetic recombination. Moreover, RECQ1-deficient cells are more sensitive to DNA damage and display spontaneously elevated sister chromatid exchanges reminiscent of aberrant repair of stalled replication forks. We hypothesize that RECQ1 plays critical roles in ensuring genome stability by virtue of its catalytic actions and specific interactions with cellular protein partners. To test this hypothesis, we are proposing systematic analyses of the biochemical and cellular characteristics of RECQ1. We will elucidate how biochemical activities of RECQ1 allow it to achieve its putative functions in genome stability maintenance by: 1) elucidating role(s) of RECQ1 in DNA repair pathways of genome stability maintenance; 2) determining critical amino acid residues of RECQ1 essential for specific catalytic and cellular functions; and 3) identifying novel protein interactions of RECQ1 using unbiased biochemical approaches and investing their functional significance. Results from these studies will be important to establish biological roles of RECQ1. This should facilitate dissecting the molecular details that explain similarities and differences in the biological functions of human RecQ helicases in pathways of genome stability maintenance to prevent cancer and premature aging. PUBLIC HEALTH RELEVANCE: RECQ1 belongs to the RecQ family of DNA helicases members of which are associated with rare diseases of premature aging and cancer predisposition in humans. Thus, the functions of RecQ helicases have a direct impact on human health. The presence of multiple RecQ homologs in humans indicates functional specialization; elucidating the molecular function(s) of RECQ1 helicase should, therefore, provide important insights to the mechanisms of genome stability maintenance that prevent development of cancer and early onset of aging.

描述(由申请人提供)：RecQ解旋酶家族是一组高度保守的DNA解旋酶，在保护所有生命王国的基因组稳定性方面至关重要。人类RecQ同源物包括RECQ1、BLM、WRN、RECQL4和RECQ5。虽然这五个人类RecQ蛋白在其催化核心上相似，并在体外具有某些生化特性，但它们显然不是多余的。BLM、WRN和RecQ4的突变分别与Bloom、Werner和Rothmund-Thomson综合征的不同遗传疾病有关。因此，一个RecQ蛋白的缺陷足以导致基因组的不稳定，而其他RecQ同源物无法弥补这一点。然而，为什么每个RecQ蛋白都是独一无二的，目前还不清楚。剖析每个人类RecQ解旋酶的功能，并比较它们之间的异同，将揭示在DNA代谢中RecQ功能的哪些方面是基因组维持所必需的。这项建议的目的是研究RECQ1的分子功能，RECQ1是人类RecQ解旋酶同源物中含量最丰富但特征最少的同系物。最近，我们发现RECQ1对于维持基因组的稳定性是必不可少的；它的缺失会导致DNA损伤的积累和染色体的不稳定。RECQ1结合和解开代表DNA重组修复中间体的DNA结构，并在物理和功能上与参与调控基因重组的蛋白质相互作用。此外，RECQ1缺陷细胞对DNA损伤更敏感，并表现出自发升高的姐妹染色单体交换，这让人想起停滞不前的复制叉子的异常修复。我们推测，RECQ1通过其催化作用和与细胞蛋白伙伴的特异性相互作用，在确保基因组稳定性方面发挥关键作用。为了验证这一假设，我们建议对RECQ1的生化和细胞特征进行系统分析。我们将通过以下几个方面阐明RECQ1的生化活性如何使其在基因组稳定性维持中实现其可能的功能：1)阐明RECQ1在维持基因组稳定性的DNA修复途径中的作用(S)；2)确定RECQ1特定催化和细胞功能所必需的关键氨基酸残基；以及3)使用无偏见的生化方法鉴定RECQ1的新的蛋白质相互作用并研究其功能意义。这些研究的结果将对确定RECQ1的生物学作用很重要。这应该有助于剖析解释人类RecQ解旋酶在维持基因组稳定性以防止癌症和过早衰老的途径中生物学功能的相似和不同的分子细节。 公共卫生相关性：RECQ1属于DNA解旋酶RecQ家族，其成员与人类罕见的早衰和癌症易感性疾病有关。因此，RecQ解旋酶的功能对人类健康有着直接的影响。在人类中存在多个RECQ同源物表明功能特化；因此，阐明RECQ1解旋酶的分子功能(S)将为维持基因组稳定以防止癌症发展和早期衰老的机制提供重要的见解。