摘要
In eukaryotes,gene expression is highly orchestrated not only by genomic promoters and enhancers but also by covalent mod-ifications added to either chromatin or RNAs.Traditionally,“epigenetics”refers to the chemical modifications that govern heritable changes in gene expression independent of the DNA sequence;“epitranscriptomics”indicates the covalent decora-tions in RNA,which plays a central role in posttranscriptional gene regulation.To date,>170 RNA chemical modifications have been characterized.Most of these modifications were originally identified in highly abundant noncoding RNA species,such as ribosomal RNAs(rRNAs),transfer RNAs(tRNAs),and small nuclear RNA(snRNAs).
