Fig. 2: Dynamics of repressive histone marks during mouse spermatogenesis.

a Snapshots of the UCSC genome browser showing the normalized ChIP-seq read densities of H3K9me2, H3K9me3, and H3K27me3 in a representative genomic region containing Oprk1 and Npbwr1 genes. Areas between H3K9me3 peaks are highlighted in light red to indicate increased H3K9me2 enrichment specifically from B to Z stages. Promoter regions, highlighted with yellow shading, are modified by H3K27me3 at various stages, excluding B to Z stages. Right panel shows a magnified view of dashed framed regions for H3K9me2 and H3K9me3 patterns in the indicated stages. SINE, LINE, and LTR elements are shown as black squares. b The numbers of H3K9me2, H3K9me3 and H3K27me3 ChIP-seq peaks at 11 stages of mouse spermatogenesis. c, d Metagene profiles showing the ChIP-seq normalized read densities of H3K9me2 on genes that are expressed (c) and repressive (d) from B to Z stages. e Alluvial plot showing the temporal dynamics of bivalent domains during mouse spermatogenesis. Each line in the plot represents a bivalent gene, and the total regions shown are those classified as bivalent genes in at least one of the analyzed stages. f Boxplot illustrating the expression levels of bivalent genes that underwent a loss of H3K27me3 modifications during the transition from A1 to B stages. g Snapshots of the UCSC genome browser showing the normalized ChIP-seq read densities of H3K4me3, H3K27me3, and H3K9me2 at A1 and pL stages on a representative bivalent gene, Fzd5. h Snapshots of the UCSC genome browser showing the normalized ChIP-seq read densities of H3K4me3 and H3K27me3 at RS8 and mature sperm stages over three representative bivalent gene loci, indicating the retained and lost bivalent states during the progression from RS8 stage to mature sperm.