Utrecht University, Science Faculty, Department Biology, Padualaan 8, NL-3584 CH Utrecht, The Netherlands.
Gen Comp Endocrinol. 2010 Feb 1;165(3):390-411. doi: 10.1016/j.ygcen.2009.02.013. Epub 2009 Apr 5.
Spermatogenesis is a developmental process during which a small number of diploid spermatogonial stem cells produce a large number of highly differentiated spermatozoa carrying a haploid, recombined genome. We characterise morphologically the different germ cell stages with particular attention for the spermatogonial generations, including the stem cells and their specific capacity to colonise a recipient's testis after transplantation. We propose a nomenclature for fish germ cells to improve the comparability among different teleost fish but also to higher vertebrates. Survival and development of germ cells depends on their continuous and close contact to Sertoli cells, and we review their multiple roles in the cystic mode of spermatogenesis seen in fish. We then discuss gene expression patterns associated with testis maturation. The endocrine system of vertebrates has evolved as master control system over spermatogenesis. In fish, both pituitary gonadotropins LH and FSH stimulate gonadal sex steroid hormone production directly by activating Leydig cells. Information is reviewed on the effects of progestin, androgens, and estrogens on global testicular gene expression patterns (microarray analysis), and on the molecular mechanisms by which steroids regulate specific candidate genes (identified by subtractive hybridization approaches) during early stages of testis maturation. Moreover, progestin and androgen effects on spermiation and milt hydration are discussed. Sex steroids mainly act via receptors expressed by Sertoli cells. One type of response is that Sertoli cells change growth factor expression, which subsequently modulates germ cell proliferation/differentiation via mechanisms yet to be characterised. Finally, we review data on germ cell autonomous processes, mainly derived from loss-of-function mutant fish lines, before identifying a number of focus areas for future research activities.
精子发生是一个发育过程，在此过程中，少数二倍体精原干细胞产生大量高度分化的精子，携带单倍体、重组的基因组。我们特别关注精原细胞世代，对不同的生殖细胞阶段进行形态学描述，包括干细胞及其在移植后殖民受体睾丸的特定能力。我们提出了鱼类生殖细胞的命名法，以提高不同硬骨鱼之间的可比性，也提高与高等脊椎动物之间的可比性。生殖细胞的存活和发育取决于它们与支持细胞的持续和紧密接触，我们回顾了它们在鱼类中所见的囊性精子发生模式中的多种作用。然后，我们讨论了与睾丸成熟相关的基因表达模式。脊椎动物的内分泌系统已经进化为精子发生的主控系统。在鱼类中，垂体促性腺激素 LH 和 FSH 通过激活间质细胞直接刺激性腺类固醇激素的产生。我们回顾了孕激素、雄激素和雌激素对全局睾丸基因表达模式（微阵列分析）的影响，以及类固醇在睾丸成熟早期调节特定候选基因（通过减法杂交方法鉴定）的分子机制。此外，还讨论了孕激素和雄激素对精子释放和精液水合的影响。性类固醇主要通过支持细胞表达的受体发挥作用。一种反应是支持细胞改变生长因子表达，随后通过尚未确定的机制调节生殖细胞的增殖/分化。最后，我们回顾了来自功能丧失突变鱼系的生殖细胞自主过程的数据，然后确定了一些未来研究活动的重点领域。
