利用線蟲為模型探討在雄性減數分裂過程的中心粒的複製

Abstract

Centriole duplication and disengagement once per cell cycle is important for maintaining the number of centrosome. The regulation mechanisms are coupled with DNA replication and segregation. However, at the end of male meiosis, four haploid sperm cells are generated with a pair of centrioles for each, implying additional centriole duplication event which was uncoupled with DNA replication. We are interested in when centriole duplication happening during male meiosis. We built up the assay which combined centrosome number and SAS-4 intensity of each centrosome as the marker for the number of centrioles. Through immunofluorescence staining of male germlines and live imaging of spermatocytes, we are able to calculate changes in centriole numbers during meiotic stages. We also developed an algorithm to automatically segment tiny centrosome signals in low signal-to-noise ratio videos. Based on our results, we found the first meiotic duplication spans through entire meiotic prophase for about twenty hours and the second duplication happened shortly after primary meiotic division for roughly ten minutes. The duplication rates and meiotic stages of two duplication events appeared very different. We thought two meiotic duplication events were both different with mitotic centriole duplication. In the future, we could apply our assay under different genetic background or chemical inhibitors to investigate the difference in the regulation mechanisms with mitosis.