ROLE OF G4-DNA IN THE PAIRING OF CHROMOSOMES

G4-DNA 在染色体配对中的作用

基本信息

批准号：
3300364
负责人：
WALTER GILBERT
金额：
$ 17.5万
依托单位：
HARVARD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1989
资助国家：
美国
起止时间：
1989-04-01 至 1992-03-31
项目状态：
已结题

项目摘要

During meiosis, after DNA replication, the pairing of chromosomes involves four copies of each chromatid, which synapse together before recombination takes place. Certain short guanine-rich motifs in single-stranded DNA self-recognize and associate in physiological salt to make four-stranded structures in which the strands run in a parallel fashion. Such four-stranded structures, named G4-DNA, are able to crosslink four Watson-Crick duplexes. Such guanine-rich sequences have been found in immunoglobulin switch regions and in the telomeres of chromosomes. It is possible that this self-recognition of G-rich motifs in DNA is used to bring together the four chromatids that must synapse in meiosis, where a series of different G4-DNA-forming regions along the entire length of a chromosome might serve as an identification pattern for pairing. G4-DNA crosslinks may also be used to align chromosomes in mitosis and in the formation of polytene chromosomes. This project will test the hypothesis that G4-DNA-forming regions serve as identification signals for chromosome matching. Anti-G4- DNA antibodies will be used to detect G4-DNA in chromosomes during meiotic pairing. Crosslinks between chromosomes involved in meiotic pairing will be isolated to investigate whether their sequences are such that they can form G4-DNA structures. Such G4- DNA-forming elements and their surrounding sequences will be cloned, and the engagement of guanines into G4-DNA in vivo will be demonstrated by in vivo dimethyl sulfate methylation experiments. The cell may control the formation of G4-DNA at special times in the cell cycle by synthesizing G4-DNA-binding proteins and special DNA melting proteins. Both proteins that recognize G4-DNA and melting proteins that relax the DNA structure in specific regions, in which one strand is unusually G-rich, will be sought. By binding the C-rich strand, such melting proteins would free the G- rich regions to seek each other out from chromatid to chromatid to make crosslinks to bring together four duplexes. The significance of the G4-DNA hypothesis is that it provides an understanding of how chromosome pairing is accomplished throughout eukaryotic organisms and explains why four chromatids are involved in recombination.

在减数分裂期间，DNA复制后，染色体配对涉及每个染色单体的四个副本，它们突触在一起在重组发生之前。某些富含鸟嘌呤的短链单链 DNA 中的基序自我识别并关联生理盐形成四链结构，其中股线以平行方式运行。这样的四链结构，称为 G4-DNA，能够交联四个 Watson-Crick 双链体。在免疫球蛋白中发现了这种富含鸟嘌呤的序列开关区域和染色体端粒中。有可能 DNA 中富含 G 的基序的这种自我识别被用来带来减数分裂中必须突触的四个染色单体在一起，其中一系列不同的 G4-DNA 形成区域沿着整个染色体的长度可以作为识别模式配对。 G4-DNA 交联也可用于排列染色体有丝分裂和多线染色体的形成。该项目将检验 G4-DNA 形成区域的假设作为染色体匹配的识别信号。抗G4- DNA 抗体将用于检测染色体中的 G4-DNA。减数分裂配对。染色体之间的交联参与将分离减数分裂配对以研究它们是否序列使得它们可以形成G4-DNA结构。这样的G4- DNA 形成元件及其周围序列将克隆，鸟嘌呤在体内与 G4-DNA 的结合将是通过体内硫酸二甲酯甲基化实验证明。细胞可能在特定时间控制G4-DNA的形成通过合成 G4-DNA 结合蛋白和特殊的细胞周期 DNA 熔化蛋白质。识别 G4-DNA 的两种蛋白质融化蛋白质，放松特定区域的 DNA 结构，其中一条链异常富含 G，将被寻找。经过结合富含 C 的链，这种熔化的蛋白质会释放 G- 丰富的区域从一个染色单体到另一个染色单体相互寻找进行交联以将四个双链体结合在一起。 G4-DNA假说的意义在于它提供了一个了解染色体配对是如何完成的真核生物并解释了为什么涉及四个染色单体重组中。