Genome-wide maps of H3K4me3, H3K9me3 chromatin states in control and Kdm4a knockout oocytes

We report the application of low input high-throughput profiling of histone modifications in mouse oocytes. Using antibodies against H3K4me3 (100 oocytes/replicate; 2 biological replicates per genotype) and H3K9me3 ( around 300 oocytes/replicate; 2 biological replicates per genotype), we find that they are mutually exclusive in oocytes and this property is lost in oocytes lacking Kdm4a. H3K9me3 is spread into regions of H3K4me3 postive open chromatin which is surprisingly, well preserved leading to a potential bivalency of scale. Altogether, KDM4A is important to keep H3K4me3 marked open chromatin clear of H3K9me3 spreading in oocytes. Examination of 2 different histone modifications in mouse MII oocytes