Figure 3.

PRC2 regulates telomere movement within the NE and homolog pairing during meiotic prophase I. (A) Zygotene spermatocytes from cryosections of P13 testis were immunostained with the antibodies indicated. The arrowheads indicate discrete telomeres. The dashed lines surround clustered telomeres. (B) Zygotene spermatocytes with clustered telomeres at the NE were quantified (n = 250). (C) Illustrative images of homolog pairing in spermatocytes analyzed by DNA FISH with a probe to detect the subtelomeric region of chromosome 1. γH2AX staining was used to identify specific stages. (D) The frequency of homolog pairing was examined in 400 spermatocytes of each stage (50 for mutant pachytene spermatocytes) using the probes to detect the mid-region and the subtelomeric region on chromosome 1. (E) Immunostaining analysis of dynamic patterns of SUN1 at the NE during meiotic prophase I progression. The dashed lines indicate clustered SUN1 foci. Bar, 5 μm. (F) Quantification of wild-type and mutant zygotene spermatocytes with clustered SUN1 foci at the NE.