精子发生
生物
生殖细胞
体细胞
生殖系
细胞生物学
干细胞
生殖细胞
细胞分裂
细胞分化
支持细胞
遗传学
细胞
基因
内分泌学
作者
Jinping Luo,Susan Megee,Ina Dobrinski
摘要
Asymmetric division of germline stem cells in vertebrates was proposed a century ago; however, direct evidence for asymmetric division of mammalian spermatogonial stem cells (SSCs) has been scarce. Here, we report that ubiquitin carboxy-terminal hydrolase 1 (UCH-L1) is expressed in type A (As, Apr, and Aal) spermatogonia located at the basement membrane (BM) of seminiferous tubules at high and low levels, but not in differentiated germ cells distant from the BM. Asymmetric segregation of UCH-L1 was associated with self-renewal versus differentiation divisions of SSCs as defined by co-localization of UCH-L1high and PLZF, a known determinant of undifferentiated SSCs, versus co-localization of UCH-L1low/− with proteins expressed during SSC differentiation (DAZL, DDX4, c-KIT). In vitro, gonocytes/spermatogonia frequently underwent asymmetric divisions characterized by unequal segregation of UCH-L1 and PLZF. Importantly, we could also demonstrate asymmetric segregation of UCH-L1 and PLZF in situ in seminiferous tubules. Expression level of UCH-L1 in the immature testis where spermatogenesis was not complete was not affected by the location of germ cells relative to the BM, whereas UCH-L1-positive spermatogonia were exclusively located at the BM in the adult testis. Asymmetric division of SSCs appeared to be affected by interaction with supporting somatic cells and extracelluar matrix. These findings for the first time provide direct evidence for existence of asymmetric division during SSCs self-renewal and differentiation in mammalian spermatogenesis. J. Cell. Physiol. 220: 460–468, 2009. © 2009 Wiley-Liss, Inc.
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