Anti-STPG4 antibodies are used in the immunodetection of the protein sperm-tail PG-rich repeat containing 4. In humans, the canonical protein has a reported length of 248 amino acid residues and a mass of 27.8 kDa. Its subcellular localization is in the nucleus and cytoplasm. Up to 2 different isoforms have been reported for this protein. It is notably expressed in the testis. STPG4 is reported to be a maternal factor that plays a role in epigenetic chromatin reprogramming during early development of the zygote. Synonyms for this target antigen include gonad-specific expression gene protein, sperm-tail PG-rich repeat-containing protein 4, uncharacterized protein C2orf61, and protein STPG4. STPG4 gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish and chimpanzee species. Some STPG4 antibodies may have been used in research and have associated citations. Immunofluorescence is a widely used application for these antibodies. Immunocytochemistry and Immunohistochemistry are also common applications.