Anti-RNMT activating mRNA cap methyltransferase subunit antibodies are used in antigen-specific immunodetection in biological samples. The target RNMT activating mRNA cap methyltransferase subunit is a known alias name of the protein RNA guanine-7 methyltransferase activating subunit, encoded by the RAMAC gene in humans. This 118-amino acid residue protein is a regulatory subunit of the mRNA-capping methyltransferase RNMT:RAMAC complex that methylates the N7 position of the added guanosine to the 5'-cap structure of mRNAs. It is localized to the nucleus of the cell. It is reported to be widely expressed in many tissue types.