For H3K4me3 ChIP-Seq in oocytes, we isolated SCP3 positive meiotic oocytes from 14 15.5 dpc females using BiTS-CHiP42 (link). Briefly, this method uses FACS to isolate nuclei on the basis of the presence of an intra-nuclear marker (in this case, anti-SCP3 (Santa Cruz: sc-74569)). Oocytes were isolated by gating for 4C nuclei with SCP3 signal above that from secondary antibodies alone. The gating strategy is outlined in Supplementary Figure 1. Kapa Hyper Prep kit (catalog #KR0961) was used to prepare the sequencing library due to the limited starting material relative to experiments in whole testis.
Testis sample preparation was performed as described previously4 (link). The following antibodies were used: anti-DMC1: Santa Cruz (C-20, sc-8973), anti-DMC1: (custom), anti-H3K4me3: Millipore (#07–473). All sequencing was performed on an Illumina HiSeq 2500 at the NIDDK genomics core.