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Functions of the BLM Helicase in Telomere Maintenance

BLM 解旋酶在端粒维护中的功能

基本信息

批准号：
8228150
负责人：
Joanna Louise Groden
金额：
$ 30.19万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-05-01 至 2015-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8228150
关键词：
Affect Age BLM gene Binding Proteins Bloom Syndrome Bloom syndrome protein Cancer Cell Growth Cell Cycle Cells Chromosome Breakage Chromosomes Complex DNA DNA Damage DNA Double Strand Break Data Double Strand Break Repair Gene Proteins Genes Genetic Recombination Genetically Engineered Mouse Genome Stability Genomics Goals Heat-Shock Proteins 90 Hereditary Disease Homologous Gene Human Human Genome Immunohistochemistry Immunologic Deficiency Syndromes Immunoprecipitation In Vitro Individual Inherited Laboratories Learning Maintenance Male Infertility Malignant Neoplasms Mammalian Cell Mediating Mitosis Modification Mutate Nonhomologous DNA End Joining Normal Cell Nucleic Acids Phospho-Specific Antibodies Phosphorylation Site Photosensitivity Post-Translational Protein Processing Predisposition Process Proteins Regulation Role Site Syndrome TEP1 gene TERF1 gene Telomerase Telomere Maintenance Telomeric Repeat Binding Protein 1 Testing Therapeutic Topoisomerase Work Yeasts helicase homologous recombination immortalized cell in vitro Assay in vitro activity in vivo mutant neoplastic novel oncology positional cloning protein complex protein expression repaired telomere

项目摘要

ABSTRACT Human BLM encodes a recQ-like DNA helicase that is important for the maintenance of genomic stability. When both copies of this gene are mutated, the resulting hereditary disease, known as Bloom's syndrome (BS), is characterized by sun-sensitivity, small stature, immunodeficiency, male infertility, and a tremendous predisposition to cancer of all sites and types. Cells from BS individuals are characterized by chromosome breakage and other chromosomal anomalies that are indicative of increased somatic recombination. Notably, telomeric associations (TAs) between homologous chromosomes are also present in non- immortalized and immortalized cells from BS individuals. Following the positional cloning of the BLM gene, our laboratory has investigated the functions of the BLM helicase in DNA double strand break repair processes such as non-homologous end joining, homologous recombination-mediated repair, and synthesis-dependent strand annealing. Our work has also suggested a role for BLM in recombination- mediated mechanisms of telomere elongation or ALT (alternative lengthening of telomeres), processes that maintain/elongate telomeres in the absence of telomerase. BLM preferentially associates with the telomere- specific binding proteins TRF1 and TRF2 in cells using ALT; its helicase activity can be modulated by these interactions. Our preliminary data identify and validate other proteins that uniquely interact with BLM and TRF2 in cells using ALT, demonstrate that these protein interactions modify enzymatic activity of BLM and its partner topoisomerase IIalpha, and show that modification of five putative phosphorylation sites can alter unwinding of DNA substrates. We hypothesize that BLM complex formation and modification occur dynamically during the specific nucleic acid transactions that are required to protect the telomere, to align chromosome sequences at homologous telomeres, to permit strand invasion and elongation, and/or ultimately to disentangle telomeres. These ideas will be investigated by analyses of BLM modification, localization and protein partnering during telomere elongation, and by modifying these interactions or modifications in vitro and in vivo using genetically engineered mice. The immediate goal of this application is to determine the mechanism by which BLM functions to maintain telomeres. This work has important implications for learning how cells maintain their genomic integrity, how they age or become immortal, and ultimately for developing better therapeutic strategies in oncology. PROJECT NARRATIVE Inherited syndromes that predispose to cancer have provided us an opportunity to study the genes and proteins that are important for keeping normal cells from becoming neoplastic. The BLM helicase is one of these proteins, as it seems to be required to maintain stability of the human genome. Its role in the maintenance of chromosome ends is especially important, as it is these mechanisms that enable cells to gain the ability to grow indefinitely. The study of BLM therefore represents an opportunity for us to learn how we can control the growth of cancer cells in a therapeutic setting.

抽象的人类 BLM 编码一种类似 recQ 的 DNA 解旋酶，这对于维持基因组稳定性非常重要。当该基因的两个拷贝都发生突变时，就会产生遗传性疾病，称为布卢姆综合症（BS），其特点是对阳光敏感、身材矮小、免疫缺陷、男性不育和巨大的所有部位和类型的癌症倾向。 BS个体的细胞以染色体为特征断裂和其他染色体异常表明体细胞重组增加。值得注意的是，同源染色体之间的端粒关联（TA）也存在于非染色体中。来自 BS 个体的永生化和永生化细胞。 BLM 基因定位克隆后，我们实验室研究了BLM解旋酶在DNA双链断裂修复中的功能诸如非同源末端连接、同源重组介导的修复等过程合成依赖性链退火。我们的工作还表明了 BLM 在重组中的作用—— 端粒延长或 ALT（端粒选择性延长）的介导机制，其过程在没有端粒酶的情况下维持/延长端粒。 BLM 优先与端粒结合使用 ALT 在细胞中特异性结合蛋白 TRF1 和 TRF2；其解旋酶活性可以通过这些调节互动。我们的初步数据识别并验证了与 BLM 独特相互作用的其他蛋白质，使用 ALT 的细胞中的 TRF2 证明这些蛋白质相互作用改变了 BLM 和它的伴侣拓扑异构酶 IIalpha，并表明五个假定的磷酸化位点的修饰可以改变 DNA 底物的解旋。我们假设发生了 BLM 复合物的形成和修饰在保护端粒所需的特定核酸交易过程中动态地调整同源端粒处的染色体序列，以允许链侵入和延伸，和/或最终解开端粒。这些想法将通过 BLM 修改的分析进行研究，端粒延伸过程中的定位和蛋白质合作，并通过修改这些相互作用或使用基因工程小鼠进行体外和体内修改。此应用程序的近期目标目的是确定 BLM 维持端粒的机制。这项工作有重要意义对了解细胞如何保持其基因组完整性、它们如何衰老或永生的影响，以及最终是为了开发更好的肿瘤学治疗策略。项目叙述易患癌症的遗传综合征为我们提供了研究基因和癌症的机会。对于防止正常细胞变成肿瘤很重要的蛋白质。 BLM 解旋酶是其中之一这些蛋白质，因为它似乎是维持人类基因组稳定性所必需的。它的作用在染色体末端的维护尤其重要，因为正是这些机制使细胞能够获得无限增长的能力。因此，BLM 的研究为我们提供了一个机会来了解我们如何可以在治疗环境中控制癌细胞的生长。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Unwinding protein complexes in ALTernative telomere maintenance.

DOI：
10.1002/jcb.22388
发表时间：
2010-01-01
期刊：
JOURNAL OF CELLULAR BIOCHEMISTRY
影响因子：
4
作者：
Bhattacharyya, Saumitri;Sandy, April;Groden, Joanna
通讯作者：
Groden, Joanna

Chromosome breakage is regulated by the interaction of the BLM helicase and topoisomerase IIalpha.

染色体断裂由 BLM 解旋酶和拓扑异构酶 IIα 的相互作用调节。

DOI：
10.1158/0008-5472.can-10-1727
发表时间：
2011
期刊：
Cancer research
影响因子：
11.2
作者：
Russell,Beatriz;Bhattacharyya,Saumitri;Keirsey,Jeremy;Sandy,April;Grierson,Patrick;Perchiniak,Erin;Kavecansky,Juraj;Acharya,Samir;Groden,Joanna
通讯作者：
Groden,Joanna

Association of BLM and BRCA1 during Telomere Maintenance in ALT Cells.