Fig. 4.

Meiotic prophase H3K4me3 marks on recombination hotspots. ChIP-qPCR analysis was performed to assess H3K4me3 levels in C57BL/6J testicular germ cells on Gapdh and Sycp1 promoter regions, on three known recombination hotspots (“Pbx1”, “Armc9-1” and “Fcgr4”), and on a recombination cold spot (“Hlx1”). For ease of graphical referral, the recombination spots are designated by the symbol for an associated or nearby gene (in quotes and not italicized, because the recombination spot is not the actual gene sequence); the actual recombination spots are defined by precise genomic position (Table 2). Early meiosis I prophase spermatocytes were enriched from 12 dpp testes of three biological samples, and subjected to ChIP-qPCR. Pachytene spermatocytes were enriched (85% purity) by unit gravity sedimentation from adult testes of three biological samples, and subjected to ChIP-qPCR. The ChIP-qPCR signal for each sequence is normalized to that for “Hlx1”, a cold spot in C57BL/6J background, used as the negative control, and shown on the y-axis as fold enrichment compared to “Hlx1”; the x-axis designates the loci assayed. *, p < 0.05; **, p < 0.01; ***, p < 0. 0.00005