SV40 T-antigen Recombinant Mouse mAb (S-6032)

SV40 large T-antigen is a multifunctional nuclear phosphoprotein encoded by the early region of simian virus 40 (SV40), with a molecular weight of approximately 90–100 kDa. It is both an essential factor for viral DNA replication and capsid assembly in permissive cells and the principal oncoprotein responsible for cell transformation and tumorigenesis by this virus in non-permissive cells. Its functions are highly modular: the amino-terminal region binds to and inactivates the host cell's key tumor suppressors pRB and p53, relieving cell cycle arrest and inhibiting apoptosis, thereby driving cells into S phase and creating a favorable environment for viral replication; the central domain confers sequence-specific DNA-binding ability and helicase/ATPase activity, enabling it to recognize the viral replication origin on its own and initiate DNA replication—a property that has made SV40 a classic model for studying the mechanisms of eukaryotic DNA replication initiation. T-antigen also contains a nuclear localization signal that allows it to enter the nucleus to carry out replication and transcriptional regulation functions, while a small fraction of T-antigen can also localize to the plasma membrane, and these two subcellular localization forms may act synergistically to mediate the full transformation phenotype. Because a single viral protein is sufficient to initiate complete DNA replication, SV40 large T-antigen has for decades been a powerful experimental tool for dissecting cell cycle regulation, tumor suppressor pathways, and eukaryotic replication mechanisms.