Molecular Basis of Robertsonian Translocation Formation

罗伯逊易位形成的分子基础

• 批准号: 6644116
• 负责人: LISA SHAFFER
• 金额: $ 29.36万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6644116
• 关键词: chromosome disorders; chromosome translocation; clinical research; cytogenetics; family genetics; fluorescent in situ hybridization; gene rearrangement; genetic mapping; genetic recombination; human genetic material tag; human subject; molecular cloning; molecular genetics; nucleic acid sequence; oogenesis; polymerase chain reaction; pulsed field gel electrophoresis; spermatogenesis

DESCRIPTION (provided by applicant): Despite the high frequency at which chromosomal abnormalities occur in humans, the molecular mechanisms underlying their occurrence are poorly understood. Robertsoman translocations (ROB), whole arm exchanges between the acrocentric chromosomes 13, 14, 15, 21, and 22, are the most common chromosomal rearrangements in humans. These rearrangements contribute greatly to fetal wastage, mental retardation, and birth defects. The formation of de novo ROB occurs at an exceptionally high rate. We have postulated that ROB form through two distinct mechanisms; a directive process resulting in the common rob(13q14q) and rob(14q21q), and a more random process resulting in the remaining eight rarer classes. To elucidate the mechanisms involved, we propose to identify the region containing the breakpoints in the two most common classes of Robertsonian translocations, rob (13q14q) and rob(14q21q) and clone the sequence(s) involved in the translocation formation. This will allow for the elucidation of the mechanism(s) of Robertsonian translocation formation and evolution of these regions on the acrocentnc chromosomes through the following specific aims: (1) Develop physical maps of the breakpoint regions in the proximal short arms of chromosomes 13, 14, and 21. (2) Determine the sequences at the rob(13q14q) and rob(14q21q) breakpoints and implicate them in ROB formation. (3) Identify factors that predispose to ROB formation through determining the mechanism through which satellite ifi DNA makes the acrocentric short arms susceptible to rearrangement. (4) Examine the spatial relationship between the acrocenthc chromosomes in oocytes and compare the frequency of meiotic exchange foci between acrocentric short arms within oocytes and between oocytes and spermatocytes. (5) Determine the evolutionary conservation of subfamilies of satellite III DNA among primates. The study of this common class of structural rearrangements has broader implications to understanding constitutional and acquired translocation formation in other regions of the genome, providing insight into recombination differences between the sexes within highly repetitive DNA, and facilitating our understanding of nondisjunction of the acrocentric chromosomes. Additionally, the cloning and mapping of sequences on the acrocentric short arms will give insight into the concerted evolution of these sequences among these chromosomes and contribute to the general understanding of chromosome evolution in mammals, and specifically in primates. Finally, this research is exploring a region of our genome that has been largely ignored by the effort of the Human Genome Project. The reagents produced in this research will contribute to the overall understanding of the organization of the human chromosome and may lead to an understanding of the role satellite DNA plays in chromosome structure, organization and function.

描述（由申请人提供）：尽管人类染色体异常发生的频率很高，但其发生背后的分子机制却知之甚少。罗伯逊曼易位 (ROB)，即近端着丝粒染色体 13、14、15、21 和 22 之间的全臂交换，是人类最常见的染色体重排。这些重组极大地导致了胎儿浪费、智力低下和出生缺陷。从头 ROB 的形成速度非常快。我们假设 ROB 通过两种不同的机制形成：指令过程产生常见的 rob(13q14q) 和 rob(14q21q)，而更随机的过程产生其余八个较稀有的类别。为了阐明所涉及的机制，我们建议识别包含罗伯逊易位的两个最常见类别 rob (13q14q) 和 rob(14q21q) 中的断点的区域，并克隆参与易位形成的序列。这将有助于通过以下具体目标阐明末端染色体上这些区域的罗伯逊易位形成和进化机制： (1) 绘制 13、14 和 21 号染色体近端短臂断点区域的物理图。 (2) 确定 rob(13q14q) 和 rob(14q21q) 断点处的序列，并将它们与 ROB 形成联系起来。 (3) 通过确定卫星 ifi DNA 使近端着丝粒短臂易于重排的机制，确定导致 ROB 形成的因素。 (4)检查卵母细胞顶端着丝粒染色体之间的空间关系，比较卵母细胞内顶端着丝粒短臂之间以及卵母细胞与精母细胞之间减数分裂交换点的频率。 (5)确定灵长类卫星III DNA亚科的进化保守性。对这种常见结构重排的研究对于理解基因组其他区域的组成性和获得性易位形成具有更广泛的意义，提供对高度重复DNA中性别之间重组差异的深入了解，并促进我们对近端着丝粒染色体不分离的理解。此外，对近端着丝粒短臂上序列的克隆和作图将有助于深入了解这些染色体中这些序列的协同进化，并有助于对哺乳动物，特别是灵长类动物的染色体进化的一般理解。最后，这项研究正在探索我们基因组中的一个区域，该区域在很大程度上被人类基因组计划的努力所忽视。这项研究中生产的试剂将有助于全面了解人类染色体的组织，并可能有助于了解卫星 DNA 在染色体结构、组织和功能中所起的作用。