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

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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