Identification and enrichment of spermatogonial stem cells displaying side-population phenotype in immature mouse testis.

In mammals, spermatogenesis is maintained by spermatogonial stem cells (SSC). In their niche, SSC divide to self-maintain and to produce a transit-amplifying population that eventually enters the meiotic cycle to give rise to spermatozoa. The low number of SSC and the lack of specific markers hinder their isolation and enrichment.