SGER: A New Approach to the Study of Meiotic Chiasma Interference

SGER：减数分裂交叉干扰研究的新方法

• 批准号: 9424330
• 负责人: James Haber
• 金额: $ 5万
• 依托单位: Brandeis University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-03-15 至 1997-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9424330&HistoricalAwards=false
• 关键词: SGER; New; Approach; Study; Meiotic

9424330 Haber This proposal presents a new approach to understanding the mechanisms of meiotic crossover interference and the connection between gene conversions and crossing-over. Interference, the inhibition of crossing-over in chromosomal regions adjacent to another crossover, has been known since early in this century, but the mechanism by which one crossover during meiosis can exert an inhibiting effect on an adjacent crossover - over distances of hundreds of kilobase pairs - is not yet understood. One of the difficulties in studying interference is that the location of double-strand breaks that initiate meiotic recombination in any given meiosis is not known, so that it is difficult to determine how one recombination event influences another. The investigator has expressed the site-specific HO endonuclease gene under the control of a meiotic-specific SPO13 promoter in order to create defined double-strand breaks in well-defined intervals, so that the relationship between gene conversion, crossing-over and interference can be studied. Preliminary studies have confirmed that the expression of SPO13::HO leads to meiotic gene conversions after premeiotic DNA replication. Moreover the investigator has shown that complete meiotic recombination can be carried out in rad50 spol3 diploids in which all normal meiotic double-strand breaks are absent; hence, examining crossing-over in the absence of any other initiating lesions is possible. This should make it possible to confirm - by indirect immunofluorescence using antibodies directed against recombination proteins - that elements of the synaptonemal complex, implicated in the establishment of interference, will assemble at the site of a double-strand break. Several aspects of this project are "high risk." First, it must first be established more precisely if SP013::HO-induced double-strand breaks are produced at the same time as normal meiotic breaks. Second, it must be established if apparent crossing-over associated with gene conversion in a rad50 spol3 background is in fact the consequence of reciprocal exchange. Finally, the detection of a single region of synaptonemal complex by cytological means may prove to be more difficult than to see many such regions in a normal meiosis. %%% Interference, the inhibition of crossing-over in chromosomal regions adjacent to another cross-over, has been known since early in this century, but the mechanism by which one crossover during meiosis can exert an inhibiting effect on an adjacent crossover - over distances of hundreds of kilobase pairs - is not yet understood. The investigation has designed an elegant series of experiments to further our understanding of this fundamental process. ***

9424330哈伯这一建议提出了一种新的方法来理解减数分裂交换干扰的机制和基因转换和交换之间的联系。自本世纪早期以来，人们就已经知道了干扰，即抑制与另一个交换相邻的染色体区域的交换，但减数分裂期间的一个交换可以对相邻的交换产生抑制作用的机制-在数百个酶对的距离上-还不清楚。研究干扰的困难之一是，在任何给定的减数分裂中启动减数分裂重组的双链断裂的位置是未知的，因此很难确定一个重组事件如何影响另一个。研究者已经在减数分裂特异性SPO 13启动子的控制下表达了位点特异性HO内切核酸酶基因，以便在明确定义的间隔内产生明确的双链断裂，从而可以研究基因转换、交换和干扰之间的关系。初步研究证实，SPO 13：：HO的表达导致减数分裂前DNA复制后的减数分裂基因转换。此外，研究者已经表明，完全减数分裂重组可以在rad 50 spol 3二倍体中进行，其中所有正常的减数分裂双链断裂都不存在;因此，在没有任何其他起始病变的情况下检查交换是可能的。 这应该可以证实--通过使用针对重组蛋白的抗体的间接免疫荧光--突触复合物的元件，参与干扰的建立，将在双链断裂的位点组装。 这个项目的几个方面是“高风险”的。首先，必须首先更精确地确定SP 013：：HO诱导的双链断裂是否与正常减数分裂断裂同时产生。其次，必须确定在rad 50 spol 3背景下与基因转换相关的明显交换是否实际上是相互交换的结果。最后，通过细胞学手段检测联会复合体的单个区域可能比在正常减数分裂中看到许多这样的区域更困难。 干扰，即抑制染色体区域中与另一个交换相邻的交换，早在本世纪就已为人所知，但减数分裂过程中的一个交换可以对相邻的交换产生抑制作用的机制--在数百个交换酶对的距离上--还不清楚。 这项研究设计了一系列优雅的实验，以加深我们对这一基本过程的理解。 ***