Anti-RNA polymerase II, I and III subunit E antibodies are used for the immunodetection of the protein encoded by the POLR2E gene. In humans, the canonical protein has a reported length of 210 amino acid residues and a mass of 24.6 kDa. Its subcellular localization is in the nucleus. A member of the Archaeal Rpo5/eukaryotic RPB5 RNA polymerase subunit protein family, it is known to be involved with protein stabilization and transcription by RNA polymerase II. Other names for this target antigen include RPB5, XAP4, hRPB25, hsRPB5, DNA-directed RNA polymerases I, II, and III subunit RPABC1, and RPABC1. Gene orthologs have been identified in the mouse, rat, bovine, frog, chimpanzee and chicken species.