Anti-Notch receptor 1 antibodies are directed against the protein encoded by the gene NOTCH1 in humans. The gene may also be known as Notch 1, Notch, AOS5, AOVD1, TAN1, hN1, and neurogenic locus notch homolog protein 1. Structurally, the protein is reported to be 272.5 kilodaltons in mass. Based on gene name, canine, porcine, monkey, mouse, and rat orthologs may also be found. The NOTCH1 antigen is a documented neural stem cell marker.