Gene expression is largely regulated by DNA methylation, transcription factor (TF), and
microRNA (miRNA) before, during, and after transcription, respectively. Although the
evolutionary effects of TF/miRNA regulations have been widely studied, evolutionary
analysis of simultaneously accounting for DNA methylation, TF, and miRNA regulations and
whether promoter methylation and gene body (coding regions) methylation have different
effects on the rate of gene evolution remain uninvestigated. Here, we compared
human–macaque and human–mouse protein evolutionary rates against
experimentally determined single base-resolution DNA methylation data, revealing that
promoter methylation level is positively correlated with protein evolutionary rates but
negatively correlated with TF/miRNA regulations, whereas the opposite was observed for
gene body methylation level. Our results showed that the relative importance of these
regulatory factors in determining the rate of mammalian protein evolution is as follows:
Promoter methylation ≈ miRNA regulation > gene body methylation > TF regulation,
and further indicated that promoter methylation and miRNA regulation have a significant
dependent effect on protein evolutionary rates. Although the mechanisms underlying
cooperation between DNA methylation and TFs/miRNAs in gene regulation remain unclear, our
study helps to not only illuminate the impact of these regulatory factors on mammalian
protein evolution but also their intricate interaction within gene regulatory
networks.