Anti-RP9 pre-mRNA splicing factor antibodies are used for the immunodetection of the protein encoded by the RP9 gene. In humans, the canonical protein has a reported length of 221 amino acid residues and a mass of 26.1 kDa. Its subcellular localization is in the nucleus. It is noted to be involved in RNA splicing. The gene encoding this protein is implicated in Retinitis pigmentosa. Other names for this target antigen include PAP1, Pim-1 kinase associated protein, pim-1-associated protein, retinitis pigmentosa 9 (autosomal dominant), and PAP-1. Gene orthologs have been identified in the mouse, rat, frog, zebrafish and chicken species.