エーゲルマン エドワード ミネソタ大学, 細胞生物学部門, 教授
ビショップ ダグラス シカゴ大学, 細胞照射線腫瘍部門, 講師
SHINOHARA Akira Faculty of Science, Osaka University, 理学部, 助手 (00252578)
OGAWA Hideyuki Faculty of Science, Osaka University, 理学部, 教授 (70028207)
BISHOP Douglas K. Department of Radiation and Cellular Oncology, Medical School, University of Chi
EGELMAN Edward H. Department of Cell Biology, Medical School, Minnesota University
In meiosis, haploid gametes are produced from diploid parental cells.In most organisms, this reductional segregation of chromosomes accompanies with genetic recombination between homologous chromosomes.The recombination that occurs in meiotic prophase 1 provides for proper distribution of chromosomes and for generation of genomic diversity.
During meiosis, chromosomes synapse and recombine using various complexes formed by recombination proteins and show a series of morphological changes.To understand the mechanisms of the recombination, we are studying the mechanisms of action of each protein that constitutes in the complexes involved in recombination and repair of damaged DNA in yeast.
By using the mouse and lily chromosomes in meiosis, we studied the relationships between morphological changes of chromosomes and the localization of the recombination proteins.We found that the Rad51 and Lim 15 proteins, that have general properties of searching and pairing of homologous DNA sequences, localize at specific positions at specific time.Both proteins on meiotic chromosomes of lily showed that these proteins participate in searching for homologous chromosomes on the leptotene stage and lead to chromosome pairing in zygotene stage.In mouse meiotic chromosomes, the Rad 51 protein becomes a component of the synaptonemal complex core in pachytene chromosomes and is involved in chiasma formation in the diplotene.On the other hand, the Lim15 protein is present only at both ends of cores in the pachytene through diplotene chromosomes even in diakinesis.The Lim15 protein is not involved in chiasma formation and instead, is involved in recombination in the telomeric region and in segregation of paired chromosomes in prophase 1.thus, it is evident that Rad51 and Lim15 play different roles in the late stages of meiotic recombination.