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，对于保护所有生命王国的基因组稳定性至关重要。人类 RecQ 同源物包括 RECQ1、BLM、WRN、RECQL4 和 RECQ5。尽管这五种人类 RecQ 蛋白的催化核心相似，并且在体外具有某些生化特性，但它们显然并不多余。 BLM、WRN 和 RecQ4 的突变分别与 Bloom、Werner 和 Rothmund-Thomson 综合征等不同的遗传性疾病相关。因此，一种 RecQ 蛋白的缺陷足以导致基因组不稳定，而这种不稳定是其他 RecQ 同源物无法弥补的。然而，每种 RecQ 蛋白的独特之处尚不清楚。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 DNA 代谢中 RecQ 功能的哪些方面对于基因组维护至关重要。该提案的目的是检查 RECQ1 的分子功能，RECQ1 是最丰富但特征最少的人类 RecQ 解旋酶同源物。最近，我们发现RECQ1对于维持基因组稳定性至关重要；它的缺乏会导致DNA损伤的累积和染色体不稳定。 RECQ1 结合并解开代表 DNA 重组修复中间体的 DNA 结构，并与参与调节基因重组的蛋白质发生物理和功能上的相互作用。此外，RECQ1缺陷的细胞对DNA损伤更敏感，并表现出自发升高的姐妹染色单体交换，让人想起停滞的复制叉的异常修复。我们假设 RECQ1 凭借其催化作用以及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着关键作用。为了检验这一假设，我们建议对 RECQ1 的生化和细胞特征进行系统分析。我们将通过以下方式阐明RECQ1的生化活性如何使其在基因组稳定性维持中实现其假定的功能：1）阐明RECQ1在基因组稳定性维持的DNA修复途径中的作用； 2) 确定对特定催化和细胞功能至关重要的 RECQ1 关键氨基酸残基； 3) 使用公正的生化方法鉴定 RECQ1 的新型蛋白质相互作用并研究其功能意义。这些研究的结果对于确定 RECQ1 的生物学作用非常重要。这应该有助于剖析分子细节，解释人类 RecQ 解旋酶在维持基因组稳定性以预防癌症和过早衰老的途径中的生物学功能的相似性和差异。 公共健康相关性：RECQ1 属于 DNA 解旋酶 RecQ 家族，该家族成员与人类罕见的早衰疾病和癌症易感性相关。因此，RecQ解旋酶的功能对人类健康有直接影响。人类中存在多个 RecQ 同源物表明功能特化；因此，阐明 RECQ1 解旋酶的分子功能应该为基因组稳定性维持机制提供重要的见解，从而预防癌症的发展和早期衰老。