from Jeffrey E. Squires and Thomas Preiss writing in Epigenetics: A Reference Manual:

A wealth of nucleobase and ribose modifications have been identified in multiple types of RNA including tRNAs, rRNAs, mRNAs, and small regulatory RNAs. Among them, 5-methylcytosine (m⁵C) has been detected in rRNAs, tRNAs, and early reports have indicated its presence in mRNAs. Well established as an epigenetic mark in DNA, the prevalence and function of m⁵C in RNA is either incompletely explored (tRNA, rRNA) or virtually unknown (mRNA, other noncoding RNA). Two eukaryotic m⁵C RNA methyltransferases have been identified; however, their substrate specificity and biological roles are incompletely understood. With recent advances in bisulfite sequencing of RNA, comprehensive analyses to determine the occurrence and functions of m⁵C in the transcriptome now appear feasible. In this chapter, we summarise the current knowledge in this field, focussing primarily on eukaryotic transcriptomes.

Further reading: Epigenetics: A Reference Manual

Tags: Epigenetics | DNA methylation | Cancer epigenetics | Early life environment | DNA methylation and behavior | Histone acetyltransferase biology | Transgenerational epigenetic inheritance | Mammalian X inactivation | Epigenetic memory in plants | Polycomb-group regulation | Centromeres and telomeres | DNA sequence contribution to nucleosome distribution | Macrosatellite epigenetics | Histones | Cell-fate specification and reprogramming | DNA methylation in cancer | Variant histone H2A and cancer development | RNA modification