Spermatogonial Stem Cells From The Proliferation Of Molecular Mechanisms

Spermatogonial stem cells (SSCs) is the only kind of adult stem cell which can take hereditary informations to descents. The research of SSCs is very important for the study of spermatogenesis, cure of certain hereditary diseases, construction of transgenic animals and generation of pluripotent stem cells. On the other hand, SSCs are very rare in mice testis (comparing 1 in 3000-4000 testicular cells) so that further study and applications are limited for the cell quantity and life span. It is necessary to explore the molecular mechanism of SSCs self-proliferation. Recently report showed that Bmi1 and Piwi gene were tightly related to SSCs proliferation, but to our knowledge the impact of these genes on SSCs proliferation was still not reported. To solve these problems, we cloned Bmi1 and Piwi gene from mice testis, prepared rBMI 1 polyclonal antibody, made a expressional exploration of Bmi1 in mice testis, constructed Bmi1 RNAi vector, constructed prokaryotic expression vector of Bmi1 and Piwi, and the impact of Bmi1 and Piwi was studied. It is the first time that Bmi1 was found to be expressed in SSCs and functioned at the initial stage of spermatogenesis, overexpression of Bmi1 could promote the proliferation of SSCs (P＜0.01), depression of Bmi1 could inhibited SSCs proliferation (P＜0.01), that means Bmi1 was a key regulator of SSCs proliferation, overexpression of Piwi could promote the proliferation of SSCs (P<0.01), the best suitable concentration of pcDNA3.1/Myc-His-Bmi1 and pcDNA3.1/Myc-His-Piwi for transfecting are 2.4 and 2.8μg/ml. This research laid foundation for the clarity of SSCs self-proliferation mechanism and construction of SSCs quantity production. This research also provided reference for the study of other stem cells.