Fig. 1

MZIP2 is specifically expressed in meiotic prophase I and localizes to chromosome axes. a, b PCR amplification to determine the relative expression level of Mzip2 mRNA in multiple mouse tissues (a) and in male germ cells at different developmental stages (b). PCR results of Gapdh is served as a loading control. E16.5 ov ovaries at E16.5, sgA spermatogonia type A, sgB spermatogonia type B, PreL pre-leptonema, L–Z leptonema to zygonema, Pac pachynema, RS round spermatids, ES elongated spermatids, RT– without reverse transcriptase, negative control. c Immunofluorescent staining of MZIP2 and SYCP3 on nuclear surface spreads of wild-type spermatocytes at indicated stages. SYCP3 marked the meiotic chromosome axes. White arrow indicates XY body. Enlarged images showed the partially or fully synapsed homologous pairs, and the regions of which were bordered with dashed lines. L leptonema, EZ early-zygonema, MZ mid-zygonema, LZ late-zygonema, EP early pachynema, LP late-pachynema. Scale bar, 10 μm. d Quantification of MZIP2 foci detected on the chromosomes of WT, Mzip2^−/−, and Spo11^−/− spermatocytes at indicated stages. Numbers of spermatocytes analyzed (n) were indicated. Z-like zygonema-like, P-like pachynema-like. Median focus numbers were marked. Error bar indicated S.E.M. P-values were assessed by unpaired two-tailed Student’s t-tests. e Immunofluorescent staining of MZIP2 on nuclear surface spreads of WT, Mzip2^−/−, and Spo11^−/− testes. White arrow indicates XY body. Scale bar, 10 μm