Arrest of Spermatogenesis at the Round Spermatid Stage in the Null Mice.

H&E staining of paraffin-embedded testes (A, A') and epididymis (B). A' is the large magnification of the box area in the A. (C) Quantitative realtime RT-PCR analysis of the germ cell differentiation markers. RNA was isolated from 3-months-old littermates. Expression levels of each gene were normalized to the levels of the 18sRNA (n = 6). Data in (C) indicate the mean±SD. * P<0.05; ** P<0.01