Figure 1

Histological abnormalities and decreased germ cell counts in newborn Dnmt3L^-/- testis. A) Hematoxylin and eosin staining of cross-sections of testes from 12 dpp Dnmt3L^+/- (left) and Dnmt3L^-/- (right) mice. Germ cells do not appear to be entering meiosis in the absence of DNMT3L (right panel). B) Immunoperoxidase staining of germ cells with the GCNA1 antibody (brown) in testis sections of 10 dpp (top) and 8 dpp (bottom) Dnmt3L^+/- and Dnmt3L^-/- mice. C) Graphical representation of germ cell counts in Dnmt3L^+/- and Dnmt3L^-/- testes. A difference in germ cell count is observed as early as 6 dpp in absence of DNMT3L. By 10 dpp, mutant males have approximately a quarter of the number of germ cells their Dnmt3L^+/- littermates have. For each time point, GCNA1-positive germ cells were counted per 2000 Sertoli cells; two to three males were examined per genotype. Results are presented as means ± SEM; mean counts for individual males are presented as dots when only two animals were analyzed.