Extended Data Figure 4: Generation of Meikin-knockout mice.

a, Schematic illustrations of the wild-type allele and targeted Meikin^−/− allele are shown. Grey boxes represent exons. The targeted exon 4 contains the intact splicing acceptor (SA) sequence followed by a premature stop codon, resulting in disruption of the Meikin allele. Black bar probe for Southern blot. b, Southern blot of genomic DNA from wild type (+/+) and Meikin heterozygous (+/−) ES cells after Pvu II digestion. ES cell clone number 2 used to generate the mice. c, Immunoblot analysis of testis extracts prepared from mice with the indicated genotypes (4-week-old). In Meikin^−/−, the specific bands probed by the anti-MEIKIN antibody are absent (shown as arrowheads). α-tubulin is a loading control. d, Testes from 12-week-old wild-type (+/+) and Meikin^−/− (−/−) mice. e, Haematoxylin and eosin staining of a section of the testis (12-week-old) showed seminiferous tubules. Enlarged pictures of seminiferous tubules showed spermatocyte (black arrowheads) and spermatids (yellow arrowheads) in wild-type and Meikin^−/−. Scale bar, 100 μm. f, Haematoxylin-eosin staining of epididymis from 12-week-old mice shows reduced number of sperms in Meikin^{−/ −}. Enlarged images of sperms are shown. Scale bar, 50 μm. g, A pair of ovaries (8-week-old) from the indicated genotypes (top). Haematoxylin and eosin–stained paraffin sections of ovaries from 8-week-old wild-type and Meikin^−/− mice (middle). The antral-stage follicles with oocyte nuclei are magnified (bottom). Asterisks indicate corpora lutea. Scale bar, 500 μm.