Profiling of H3K4me3 and H3K27me3 and their roles in regulating gene transcription in allotetraploid cotton (RNA-Seq)

Cotton is an excellent model for studying heterosis, crop domestication and bioengineering improvement. Chromatin profiling helps to reveal how histone modifications are involved in controlling differential gene expression between A and D subgenome in allotetraploid cotton. However, the detailed profiling and functional characterization of H3K27me3 and H3K4me3/H3K27me3 bivalent mark are still understudied in cotton. In this study, we conducted H3K4me3 and H3K27me3-related ChIP-seq followed by comprehensively characterizing their roles in regulating gene transcription in cotton. We found that H3K4me3 and H3K27me3 exhibited active and repressive roles in regulating expression of genes between A and D subgenome, respectively. Expression of H3K4me3-H3K27me3 bivalent genes was regulated by combinatorial actions of both marks and may be dominantly controlled by H3K4me3. More importantly, H3K4me3 exhibited enrichment levels, positioning and distance-related effects on expression levels of related genes. In addition, H3K4me3, H3K27me3 and bivalent mark can indirectly influence gene expression through TF-mediated regulatory networks. Thus, our study provides insights in functions of H3K4me3 and H3K27me3 in regulating differential gene expression between A and D subgenome in cotton. Overall design: RNA-seq,ChIP-seq