摘要：SummaryDNA methylation is an important epigenetic modification. However, the regulations and functions of insect intragenic DNA methylation remain unknown. Here, we demonstrate that a regulatory mechanism involving intragenic DNA methylation controls ovarian and embryonic developmental processes inBombyx mori. InB. mori,DNA methylation is found near the transcription start site (TSS) of ovarian genes. By promoter activity analysis, we observed that 5′ UTR methylation enhances gene expression. Moreover, methyl-DNA-binding domain protein 2/3 (MBD2/3) binds to the intragenic methyl-CpG fragment and recruits acetyltransferase Tip60 to promote histone H3K27 acetylation and gene expression. Additionally, genome-wide analyses showed that the peak of H3K27 acetylation appears near the TSS of methyl-modified genes, and DNA methylation is enriched in genes involved in protein synthesis in theB. moriovary, with MBD2/3 knockdown resulting in decreased fecundity. These data uncover a mechanism of gene body methylation for regulating insect gene expression and reproduction.Graphical AbstractDisplay OmittedHighlights•Insect intragenic 5mC enhances gene expression through histone H3K27 acetylation•MBD2/3 binds the intragenic 5mC and recruits Tip60 to promote H3K27 acetylation•Intragenic 5mCs modify protein synthesis-related genes in insect ovaries•The intragenic 5mC plays a role in insect reproductionEntomology; molecular mechanism of gene regulation; omics
