miRNAs are a class of noncoding RNAs of approximately 19-22 nucleotides that are widely found in animals, plants, bacteria and even viruses. Dysregulation of the expression profile of miRNAs is importantly linked to the development of diseases. Epigenetic modifications regulate gene expression and control cellular phenotypes. Although miRNAs are used as an epigenetic regulation tool, the biogenesis of miRNAs is also regulated by epigenetic events. Here the authors review the mechanisms and roles of epigenetic modification (DNA methylation, histone modifications), RNA modification and ncRNAs in the biogenesis of miRNAs, aiming to deepen the understanding of the miRNA biogenesis regulatory network.
Keywords: DNA methylation; RNA methylation; histone modification; miRNA biogenesis; ncRNAs.
Genes are divided into coding genes and noncoding genes, and people have always focused on coding genes because coding genes guide the synthesis of proteins and proteins are the main bearers of life activities. However, the fact that such important coding genes occupy only 2% of the large human genome shows that noncoding genes are far more complex and important than we think. Through scientific exploration, it has been found that noncoding genes are an important part of gene expression regulation. The end products of noncoding genes, such as miRNAs, also have their own expression patterns at different stages of the body's development, and an imbalance in expression patterns often causes various diseases. There are multiple levels of gene expression regulation during noncoding RNAs biogenesis, and this paper fully reviews the role and the mechanisms of gene expression regulation in miRNA biogenesis. Familiarity with gene expression regulation in miRNA biogenesis is important to understand the mechanisms of dysregulation of miRNA expression profiles in diseases and the treatments employed.