CxxC Finger Protein 1-mediated Histone H3 Lysine-4 Trimethylation is Essential for Proper Meiotic Crossover Formation in Mice

CXXC finger protein 1 (Cfp1) is a DNA-binding component of the SETD1 methyltransferase complex, targets SETD1A/B to most CpG islands (CpGI), and mediates the generation of H3K4me3. Deficiency of CFP1 in mice leads to pre-implantation lethality. Previous data suggest an indispensable role of CFP1 in germ cell development and meiosis. However, it remains unclear if CFP1-mediated H3K4 trimethylation is also required for the earliest stages of meiosis in both male and female germ cells. Here, we revealed that Cxxc1 deletion caused a decrease of H3K4me3 levels in spermatocytes after the zygotene stage, impaired double strand breaks (DSBs) repairing, and crossover formation in meiotic prophase. As the results, Cxxc1-deleted spermatocytes failed to complete meiosis and were arrested at the meiosis II. ChIP-seq results revealed that H3K4me3 globally descreased at transcriptional start sites in Cxxc1-null spermatocytes at the leptotene/zygotene and pathytene stages.RNA-seq at different stages revealed an earlier expression of genes within the spermatogenesis pathway in Cxxc1-null spermatocytes. These results indicated that CFP1 is required for H3K4me3 accumulation at the gene promoters of male germ cells and play a key role in regulating programed gene expression that is essential for spermatogenesis. Overall design: We examined H3K4me3 and transcriptomes in WT and Cxxc1-null spermatocytes at different stages.