Metotic Spindle Assembly and Aneuploidy in Mammals

哺乳动物减数分裂纺锤体组装和非整倍性

• 批准号: 6630420
• 负责人: Duane A. Compton
• 金额: $ 11.85万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6630420
• 关键词: DNA; SDS polyacrylamide gel electrophoresis; aneuploidy; cell cycle; cell cycle proteins; chromosome movement; egg /ovum; gene mutation; genetically modified animals; growth /development; histochemistry /cytochemistry; kinesin; laboratory mouse; mitotic spindle apparatus; polymerase chain reaction; polymerization; western blottings

DESCRIPTION (provided by applicant): It has been estimated that 15-20 percent of all human conceptions are chromosomally abnormal (aneuploid), and that many of these abnormalities occur because of errors in chromosome segregation during female meiosis. One of the strongest predictors of aneuploidy is maternal age with nearly half of all oocytes ovulated in women over age 40 containing errors in chromosome number. Most aneuploid conceptions die before birth, but several specific aneuploid states (e.g. trisomy 21) are viable and, as a class, represent the most common cause of mental retardation in man. Despite this clinical importance, very little is known about the cause of chromosome nondisjunction during female meiosis or why the rate of non-disjunction increases with maternal age. One model proposed to explain the correlation between maternal age and frequency of chromosome nondisjunction suggests that the efficiency of folliculogenesis (the development of the oocyte within the follicle in the ovary) is reduced in older women. We hypothesize that reduced or impaired folliculogenesis could contribute to chromosome non-disjunction by reducing the quantities of specific microtubule motor proteins necessary for alignment and/or segregation of chromosomes on the meiotic spindle. To test this hypothesis, we propose to use transgenic mouse technology to specifically perturb the function of the kinesin-related proteins Kid and MCAK during female meiosis. We are targeting Kid and MCAK because they are not necessary for overall spindle assembly, but are required for efficient chromosome alignment and/or segregation during mitosis and, in some non-mammalian systems, meiosis. We will specifically perturb the function of Kid or MCAK during female meiosis by transgenic expression of anti-sense or dominant negative constructs using a mouse oocyte-speciflc promoter. We will evaluate the consequences of disrupted motor function during female meiosis by examining the fertility of transgenic females, the frequency and type of birth defects in pups born from transgenic females, and the alignment of chromosomes on meiotic spindles in oocytes from transgenic females. Successful completion of these experiments will validate the application of transgenic mouse technology to study the mechanisms of spindle assembly during female meiosis in mammals and could increase our understanding of the etiology of disorders such as Down?s Syndrome.

描述(由申请人提供)：估计有15%-20% 在所有人类受孕中，有那么多是染色体异常的(非整倍体) 这些异常的发生是由于在染色体分离过程中的错误 雌性减数分裂。预测非整倍体的最有力因素之一是母亲的年龄。 在40岁以上的女性中，近一半的卵子排卵过程中存在错误 在染色体数目上。大多数非整倍体胚胎在出生前就会死亡，但也有几个 特定的非整倍体状态(例如21三体)是可行的，作为一类， 是导致人类精神发育迟滞的最常见原因。尽管如此 临床重要性，对染色体的病因知之甚少 雌性减数分裂不分离或为什么不分离的比率 随着产妇年龄的增长而增加。 一个模型被用来解释产妇年龄和 染色体不分离的频率表明， 卵泡发生(卵泡内卵母细胞的发育 卵巢)在老年女性中减少。我们假设减少或削弱 卵泡发生可能通过减少染色体数目而导致染色体不分离。 对齐所需的特定微管马达蛋白的数量 和/或减数分裂纺锤体上的染色体分离。为了测试这一点 假设，我们建议使用转基因小鼠技术来特定地 扰乱女性肌动蛋白相关蛋白Kid和MCAK的功能 减数分裂。我们的目标是Kid和MCAK，因为它们不是 整个纺锤体组件，但有效的染色体配对是必需的 和/或有丝分裂期间的分离，在一些非哺乳动物系统中，减数分裂。 我们将在雌性减数分裂过程中专门干扰Kid或MCAK的功能 通过反义或显性负向构造的转基因表达 小鼠卵母细胞特异性FLC启动子。我们将评估中断的后果 通过检测转基因植株的可育性来研究雌性减数分裂过程中的运动功能 转基因幼崽出生的雌性、出生缺陷的频率和类型 雌体和减数分裂纺锤体上的染色体对齐 转基因雌性。 这些实验的成功完成将验证 转基因小鼠技术研究纺锤体组装的机制 哺乳动物的雌性减数分裂，可以增加我们对病因学的理解 唐氏S综合征等疾病的诊断。