Figure 4.

Discrete MEI4 foci on chromosome axes of spermatocytes at leptonema and zygonema. MEI4 was detected in leptotene or zygotene spermatocytes (A–D) and oocytes at E16 (E–H). MEI4 was not observed on the axes of autosomes and sex chromosomes (white rectangle) at pachynema (I), and in spermatocytes from Mei4^−/− mice (J). (K) Foci revealed by the anti-MEI4 antibody were quantified in wild-type at leptonema (mean = 309 foci per nucleus, n = 51), zygonema (mean = 114, n = 28), and pachynema (mean = 24, n = 36). Counts included all nuclear foci, of which 67%, 49%, and 14% were on axes at leptonema, zygonema, and pachynema, respectively. On average, 20 and 14 foci per nucleus were detected in the control experiment using Mei4^−/− leptotene and zygotene-like nuclei, of which 20% and 23% were axis-associated, respectively. The anti-SYCP3 antibody was used to detect axial elements. (A,C,E,G:) Anti-MEI4 antibody alone. (B,D,F,H,I,J) Anti-MEI4 and anti-SYCP3 antibodies.