Fig. 2.

Spo11-Cre is expressed in meiotic germ cells. (A) Semiquantitative PCR of cDNA prepared from 3, 5, 7, 10 d.p.p. and adult testes (left and middle) and from 12.5, 13.5, 16.5 d.p.c. and 1 d.p.p. ovaries (right). Cre and Spo11 alpha and beta isoform mRNA (Bellani et al., 2010; Romanienko and Camerini-Otero, 2000) amplifications are shown. Actin PCR was used as a loading control. (B) β-gal-stained sections of seminiferous tubules of adult testis counterstained with nuclear Fast Red. Black arrows indicate β-gal-negative spermatogonia and somatic Sertoli cells; black and white arrowheads show β-gal-positive pachytene spermatocytes and spermatids, respectively. Asterisk indicates lepto-zygotene spermatocytes. (C) EYFP expression in testis from a 21 d.p.p. male. White and yellow arrowheads indicate pachytene spermatocytes and spermatids, respectively. White asterisk shows early meiotic spermatocytes and white arrows indicate spermatogonia or preleptotene cells. (D) β-gal-stained sections of adult ovaries counterstained with nuclear Fast Red. PF, primordial follicles; PrF, primary follicles; SF, secondary follicles. (E) EYFP expression in fetal ovaries from 14.5 d.p.c. mice. Arrowheads indicate meiotic oocytes and the asterisk, early meiotic preleptotene cells. The cell types were recognized by differential Hoechst 33342 staining of the nuclei. Scale bars: 100 μm in B and D; 10 μm in E.