NANOS is known to be required for germline cell development in a variety of animal species and for the maintenance of germline stem cells in Drosophila. The recent study by Sada et al. has demonstrated that NANOS2, one of the three mammalian homologues, is required intrinsically for maintaining adult mouse spermatogonial stem cell self-renewal.

introduction: transplantation of germ cells restores the male fertility. nevertheless, a lot of questions remain incompletely resolved. the aim of this study was to evaluate in vitro colonization efficiency of germ cells and sperm production capacity of spermatogonial cells before and after culture by sperm number assay in epididymis of recipient mice. materials and methods: we developed a sert...

The complex processes of spermatogenesis are regulated by various factors. The aim of the current study is to determine the effect of epidermal growth factor (EGF) on spermatogonial proliferation and clarify the mechanism causing the proliferation in newt testis. In the organ culture, EGF stimulated spermatogonial proliferation, but not their differentiation into spermatocytes. cDNA cloning ide...

BACKGROUND Spermatogonial stem cells (SSCs) continuously undergo self-renewal division to support spermatogenesis. SSCs are thought to have a fixed phenotype, and development of a germ cell transplantation technique facilitated their characterization and prospective isolation in a deterministic manner; however, our in vitro SSC culture experiments indicated heterogeneity of cultured cells and s...

The existence of two classes of spermatogonial stem cells in the rat testis, i.e., reserve type A0 spermatogonia and renewing, types A1-A4 spermatogonia, postulated by Clermont and Bustos-Obregon ('68), was reexamined in a quantitative analysis of type A spermatogonia in both whole mounts of tubules and in radioautographed sections of testes from animals killed at various times, up to 26 days, ...

Spermatogonial stem cells (SSCs) are in the beginning of a complex process in which they transmit genetic information from generation to generation. Any failure in this process can result in infertility. It has been suggested that transplantation of spermatogonial stem cells, following their maintenance and culturing, may restore fertility in some infertile patients. Because fertility restorati...

Mammalian spermatogenesis--the transformation of stem cells into millions of haploid spermatozoa--is elaborately organized in time and space. We explored the underlying regulatory mechanisms by genetically and chemically perturbing spermatogenesis in vivo, focusing on spermatogonial differentiation, which begins a series of amplifying divisions, and meiotic initiation, which ends these division...

spermatogonial stem cells (sscs) maintain spermatogenesis throughout life in the male. maintenance of sscs and induction of spermiogenesis in vitro may provide a therapeutic strategy to treat male infertility. this study investigated in vitro differentiation of mouse sscs in presence or absence of sertoli cells, hormones and vitamins. spermatogonial populations were enriched from testes of 4-6 ...

Germ cell and embryonic stem cells are inextricably linked in many aspects. Remarkably both can generate all somatic cell types in organisms. Yet the molecular regulation accounting for these similarities is not fully understood. Cyclin K was previously thought to associate with CDK9 to regulate gene expression. However, we and others have recently shown that its cognate interacting partners ar...