Evidence for the association of chromatin and microRNA regulation in the human genome.

Both microRNAs (miRNAs) and chromatin regulation play important roles in cellular processes and they function at different regulatory levels of transcription. Although efforts have been devoted to the investigation of miRNA and chromatin regulation, there's still no comprehensive work to illustrate their relationships due tothe lack of whole-genome wide datasets in different human cellular contexts. Based on the recently published large-scale epigenetic data, we examined the association between miRNA and epigenetic machinery. Our work confirmed a general relationship between miRNA biogenesis and chromatin features around pre-miRNA genomic regions. Obvious enrichments of DNA methylation and several histone modifications were observed within the pre-miRNA genomic region, which werecorrelated with miRNA expression levels. Furthermore, chromatin features at genepromoter regionsweretightly associated with miRNA regulation. Interestingly, we found that genes with their promoter regions located in the active chromatin state regions tend to have a higher probability to be targeted by miRNAs. This worksuggests that miRNAs and chromatin features are often highly coordinated, which provides a guide to deeply understand the complexity of gene regulation.