Epitranscriptomic

Epitranscriptomics is the field that studies chemical modifications to RNA molecules and how these modifications regulate gene expression after transcription. These modifications occur on messenger RNA, transfer RNA, ribosomal RNA, and various noncoding RNAs, and they influence RNA processing, stability, localization, translation efficiency, and splicing. The regulatory layers are dynamic and context-dependent, responding to developmental cues, environmental stimuli, and cellular state.

The most widely studied modification is N6-methyladenosine (m6A), but numerous other marks exist, including N1-methyladenosine (m1A), 5-methylcytosine (m5C), pseudouridine, and 2'-O-methylations. Enzymes that install modifications are termed writers, those that remove marks are erasers, and proteins that recognize and bind modified RNA are readers. For example, the METTL3–METTL14 writer complex deposits m6A, FTO and ALKBH5 act as erasers, and YTH domain-containing proteins serve as readers. These interactions can alter RNA splicing, export from the nucleus, translation initiation, and mRNA decay, thereby shaping gene expression programs.

Biological significance spans development, stem cell fate, immune responses, metabolism, and disease, including cancer and neurological disorders. Epitranscriptomic marks are often dynamic and responsive to stress, cellular differentiation, and circadian rhythms. Technologies such as MeRIP-seq, miCLIP, and direct RNA nanopore sequencing enable mapping of RNA modifications, while databases and computational tools integrate epitranscriptomic data to elucidate regulatory networks.