Howard Hughes Medical Institute Research Laboratories, Department of Embryology, Carnegie Institution, Baltimore, Maryland 21218, USA.
Cold Spring Harb Perspect Biol. 2011 Nov 1;3(11):a002642. doi: 10.1101/cshperspect.a002642.
Sperm and egg production requires a robust stem cell system that balances self-renewal with differentiation. Self-renewal at the expense of differentiation can cause tumorigenesis, whereas differentiation at the expense of self-renewal can cause germ cell depletion and infertility. In most organisms, and sometimes in both sexes, germline stem cells (GSCs) often reside in a defined anatomical niche. Factors within the niche regulate a balance between GSC self-renewal and differentiation. Asymmetric division of the germline stem cell to form daughter cells with alternative fates is common. The exception to both these tendencies is the mammalian testis where there does not appear to be an obvious anatomical niche and where GSC homeostasis is likely accomplished by a stochastic balance of self-renewal and differentiation and not by regulated asymmetric cell division. Despite these apparent differences, GSCs in all organisms share many common mechanisms, although not necessarily molecules, to guarantee survival of the germline.
精子和卵子的产生需要一个强大的干细胞系统，该系统需要在自我更新和分化之间取得平衡。以自我更新为代价进行分化会导致肿瘤发生，而以自我更新为代价进行分化会导致生殖细胞耗竭和不孕。在大多数生物体中，生殖干细胞（GSCs）通常存在于一个特定的解剖位置。龛内的因素调节 GSC 自我更新和分化之间的平衡。生殖干细胞的不对称分裂形成具有不同命运的子细胞是很常见的。这两种趋势的例外是哺乳动物睾丸，那里似乎没有明显的解剖位置，GSC 稳态可能是通过自我更新和分化的随机平衡来实现的，而不是通过调节不对称细胞分裂来实现的。尽管存在这些明显的差异，但所有生物体的 GSCs 都有许多共同的机制，尽管不一定是分子机制，以保证生殖系的存活。
