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RECQ样DNA解旋酶，这对于维持基因组稳定性很重要。当该基因的两个副本都被突变时，由此产生的遗传性疾病（称为布卢姆综合症）（BS）的特征是太阳敏感性，身材矮小，免疫缺陷，男性不育症和巨大所有地点和类型的癌症的易感性。 BS个体的细胞以染色体为特征断裂和其他表明体细胞重组增加的染色体异常。值得注意的是，在非 - 来自BS个体的永生和永生的细胞。遵循BLM基因的位置克隆，我们的实验室研究了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以及依赖于合成的链退火。我们的工作还提出了BLM在重组中的作用 - 端粒伸长或ALT的介导机制（端粒的替代延长），该过程是在没有端粒酶的情况下，保持/拉长端粒。 BLM优先与端粒相关联使用ALT在细胞中的特定结合蛋白TRF1和TRF2；它的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唯一相互作用的其他蛋白质使用ALT中的TRF2在细胞中，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，并表明修改五个推定的磷酸化位点可以改变解开DNA底物。我们假设发生BLM复合物的形成和修改在保护端粒所需的特定核酸交易中动态动态同源端粒的染色体序列，以允许链入侵和伸长和/或最终要解开端粒。这些想法将通过BLM修改的分析来调查，端粒伸长过程中的本地化和蛋白质合作，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饰。此应用程序的直接目标是确定BLM在维持端粒的功能的机制。这项工作很重要学习细胞如何维持其基因组完整性，它们的年龄或不朽以及最终为了制定肿瘤学方面的更好的治疗策略。项目叙述容易患癌症的遗传综合征为我们提供了研究基因和对于防止正常细胞成为肿瘤很重要的蛋白质。 BLM解旋酶是一种这些蛋白质，似乎需要维持人类基因组的稳定性。它在染色体末端的维护尤其重要，因为这些机制使细胞能够获得无限期增长的能力。因此，对BLM的研究是我们学习我们如何学习的机会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.