Basic Mechanisms of Genetic Recombination

基因重组是一种基本的机制，通过这种机制，一个有机体的亲本性状可以遗传给后代。它提供了一种在物种中传播有利等位基因和消除不利等位基因的手段。因此，重组一定在基因组的进化中起着至关重要的作用。重组还涉及细胞的各种生物功能。它参与DNA损伤的修复、DNA复制的引物形成、基因产物多样性的产生、基因的替代表达以及减数分裂i中的染色体分离。因此，对重组的研究对于理解其生物学功能机制至关重要。为了进一步了解基因重组的基本问题，我们在这笔拨款的支持下组织了一个研究小组。本课题组取得的主要突出成果如下：1。重组基因recA的同源基因已成功从酵母、鸡、小鼠和人类中克隆出来。揭示了RecA形成的重组中间体向重组分子的分解过程。在小鼠17.4染色体上发现并鉴定了雌性小鼠特有的重组热点。建立了两种用于基因重组研究的新方法。(1)利用大肠杆菌recE途径获得多种同源嵌合体基因的简便方法。(2)建立了一种利用凝胶内竞争再结合法克隆高等真核生物基因重排位点的综合方法。鉴定并分析了多种重组蛋白，如：酿酒酵母中STPbeta的S.pombe同源物Dhpl、酿酒酵母中Dmcl的百合同源物Lim15、黑腹酵母中Su(H)的小鼠同源物RBP-Jkappa。本课题在高等真核生物的基本重组机制、重组方法和重组机制分析等方面取得了重大进展。少

Genetic recombination is a fundamental mechanism by which parental traits of an organism are distributed to offspring. It provides a means of spreading a favorable allele and of eliminating an unfavorable allele in aspecies. Recombination must therefore have playd a crucial role in evolution of the genome. Recombination is also involved in various biological functions in a cell. It participates in repair of DNA damage, a primer formation of DNA replication, production of gene product diversities, alternative gene expression, and chromosome disjunction in meiosis I.Thus the study of recombination is crucial for thge understanding of the mechanisms of biological functions. To further our knowledge of fundamental problems of genetic recombination, a research group was organized supported by this grant. Main distingushed results obtained by this reserach group are as follows.1. The homologues of the recombination gene, recA, were successfully cloned from yeasts, chicken, mouse and human.2. … More A process of resolution of recombination intermediates formed by RecA to recombinant molecules are revealed.3. A recombinaion hot spot specific to mouse female was found and identified at the nucleotide sequence level on the chromosome 17.4. Two novel methods useful for study of genetic recombination were established.(1) A simple and easy method to get various chimera genes between homologues using a recE pathway of E.coli.(2) A comprehensive method to clone a specific site that made a genetic rearrangement from higher eukaryotes was estabilshed using in-gel competitive reassociation method.5. Various kinds of recombination proteins were identified and analyzed : for instance, Dhpl (S.pombe homologue of STPbeta in S.cerevisiae), Lim15 (lily homologues of Dmcl in S.cerevisiae), and RBP-Jkappa(mouse homologue of Su(H) in D.melanogaster).Thus a great advancement was made in analysis of basic recombination mechanism, methodology, and analysis of recombination mechanism in higher eukaryotes by this project. Less