人类常染色体上存在精子发生关键基因，但为医学伦理所限，多数基因及其作用尚不明了。人类胚胎干细胞（hESC）可体外分化为精子细胞，是研究人类精子发育调控的理想模型。本项目组前期建立了少弱精症特异hES系（CCRM27）：该系来源胚胎核型为46，XY，t（1；18）（p12；q22），其捐赠父亲患少弱精症；CCRM27具有hESC的典型特征且G带分析显示正常核型（46，XY）；其向精子分化过程中，精子发生关键基因DAZL的表达显著下调、DAZL阳性细胞比例降低。我们推测：CCRM27建系过程中，1、18号染色体发生二次易位恢复“正常”核型，但易位断裂点缺失了精子发生关键基因，致体外精子分化异常；该关键基因可能通过DAZL起作用。本项目将通过诱导分化技术明确CCRM27向精子分化特征，同时利用高精度测序技术捕获易位断裂点上调控精子发生的关键基因，并进一步在细胞及小鼠模型上验证其作用及机制。

There are crucial genes for spermatogenesis on human autosomes. However most of them, as well as their function mechanisms are unknown because of ethical restriction on human research. Human embryonic stem cells (hESCs) can differentiate into germ cells in vitro. And the differentiation processes reflect the development behaviors in vivo. Thus hESC is an good model to investigate the regulation mechanism of spermatogenesis. An asthenospermia-specific hES line (CCRM27) was established in our lab：it derived from embryo with 46，XY，t（1；18）（p12；q22） karyotype, donated by a couple suffered from severe asthenospermia; it shows typical hESC’ characterizations and with normal karyotype 46，XY; however, the RNA and protein expression level of DAZL key gene for spermatogenesis was repressed during CCRM27 differentiation into sperm cells.We hypothesis that there is a second balanced translocation between chr. 1 and Chr. 18 at the same breakpoints.Thus the CCRM27 karyotype looks “normal”, however genomic DNA microdeletion arise at the breakpoints on which important genes for spermatogenesis reside. We further predict that the deleted key genes regulate spermatogenesis through DAZL. Induced sperm cells differention, high precision genomic DNA/mRNA sequencing, cell and animal level experiments will be employed to testify our speculation.