Analysis of Enzymes functioning in meiosis-specific DNA recombination and isolation of their genes.

在减数分裂前期，同源染色体配对和相互重组发生频率高（体细胞重组的100-1000倍）。这种重组至少发生在每对同源物上的一个点上。如果没有稳定的同源配对，基因重组、染色体的正常分离和生殖细胞的形成就不会发生，因此生物体就会变得不育。在最近的研究期间，我们成功制备了从减数分裂细胞核中分离的抗突触复合体（s.c）的单克隆抗体（1个IgG和3个IgM）。虽然从酵母菌到人类的所有s.c c具有几乎相同的结构，表明存在共同的成分，但该抗体仅对百合s.c c起反应，而对从所有被测生物中获得的s.c c不起反应。我们还发现了拓扑异构酶和分解酶，它们的活性在减数分裂阶段增加。减数分裂细胞和体细胞具有不同的dna重组酶。我们克隆了人类肝炎病毒中能够改变病毒性质的特定区域到突变的pBR322质粒中，并在体外测量了重组频率。我们发现，与从病毒其他区域获得的DNA片段插入相比，从这两个细胞中获得的重组酶插入的频率增加了2-5倍。35S启动子刺激体细胞基因表达，但不刺激减数分裂基因表达。我们发现mei2启动子在引入减数分裂细胞后有助于高等植物基因的表达。我们已经克隆了17个减数分裂特异性基因，并对它们进行了测序。同源性分析表明，其中3个与已知蛋白基因有显著的相似性，其余为全新的蛋白基因。一旦确定了它们的启动子，我们将研究它们在减数分裂中的作用

During prophase of meiosis, the homologous chromosomes pair and the reciprocal recombination occurs at high frequency (100-1000 times of somatic recombination) . Such recombination occurs at least one point on each paired homologs. Without stable homologous-pairing, genetic recombination, normal segregation of chromosomes, and formation of reproductive cells do not occur, and thus an organism becomes sterile. During the last study-period we have successfully prepared monoclonal antibodies (one IgG and three IgM) against synaptonemal complex (S. C.) isolated from meiotic nuclei. Although all S. C. from yeast to human have practically identical structure suggesting the presence of common components, this antibody reacted only to lily S. C. but not to S. C. obtained from all organisms tested. We have found topoisomerase and resolvase in S. C. and their activities increased during meiotic pr ophase.Meiotic cells and somatic cells have different DNA-recombination enzyme (s) . We have cloned the specific region in human hepatitis virus, shown to alter the nature of virus, into the mutated pBR322 plasmids and measured the recombination frequency in vitro. We have found 2-5 times increase in the frequency with recombination enzymes from both cells in comparison with the insertion of DNA fragments obtained from other region of virus.35S promoter stimulated somatic gene expression but not meiotic ones. We have found that mei2 promoter helps to express genes in higher plant when introduced into meiotic cells. We have cloned 17 meiosis-specific genes and sequenced all of them. The homology search indicated that three of them had significant similarities with the known protein genes but the others were completely new. AS soon as their promoters are identified, we will study their function in meiosis