Anti-RNA polymerase II, I and III subunit H antibodies are used for the immunodetection of the protein encoded by the POLR2H gene. In humans, the canonical protein has a reported length of 150 amino acid residues and a mass of 17.1 kDa. Its subcellular localization is in the nucleus. Alternative splicing is reported to yield 5 different isoforms for this protein. A member of the Eukaryotic RPB8 RNA polymerase subunit protein family, it is known to be involved with transcription by RNA polymerase II. Other names for this target antigen include RPB17, RPB8, DNA-directed RNA polymerases I, II, and III subunit RPABC3, DNA-directed RNA polymerase II subunit H, and RPABC3. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.