RNMT-dependent RNA cap methylation in health and disease

RNA cap formation on RNA polymerase II transcripts is regulated by cellular signalling pathways during development and differentiation, adaptive and innate immune responses, during the cell cycle and in response to oncogene deregulation. Here, we discuss how the RNA cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), functions to complete the 7-methyl-guanosine or m7G cap. The mechanisms by which RNMT is regulated by signalling pathways, co-factors and other enzymes are explored. The m7G cap protects RNA pol II-transcribed RNA from the initiation of transcription and recruits proteins that mediate RNA processing including splicing, 3' cleavage and polyadenylation, nuclear export and translation initiation. Regulation of RNMT has gene-specific impacts with implications for cell function, cell physiology and cell fate decisions.