Anti-nucleolin antibodies are used for the immunodetection of the protein encoded by the NCL gene. In humans, the canonical protein has a reported length of 710 amino acid residues and a mass of 76.6 kDa. Its subcellular localization is in the nucleus and cytoplasm. It is noted to be involved in angiogenesis and the regulation of transcription. Post-translational modifications have been described, including methylation. Other names for this target antigen include C23 and Nsr1. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.