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SV40 large T antigen (Simian Vacuolating Virus 40 TAg) is a hexamer protein that is a proto-oncogene derived from the polyomavirus SV40 which is capable of transforming a variety of cell types. The transforming activity of TAg is due in large part to its perturbation of the retinoblastoma (pRB) and p53 tumor suppressor proteins. In addition, TAg binds to several other cellular factors, including the transcriptional co-activators p300 and CBP, which may contribute to its transformation function.〔Ali SH, DeCaprio JA (2001). "Cellular transformation by SV40 large T antigen: interaction with host proteins". Semin Cancer Biol 11 (1): 15 - 23. ref: http://www.mcb.uct.ac.za/cann/335/Papovaviruses.html〕 TAg is a product of an early gene transcribed during viral infection by SV40, and is involved in viral genome replication and regulation of host cell cycle. SV40 is a double-stranded, circular DNA virus belonging to the Polyomaviridae (earlier Papovavirus) family, Orthopolyomavirus genus. Polyomaviruses infect a wide variety of vertebrates and cause solid tumours at multiple sites. SV40 was isolated by Sweet and Maurice Hilleman in 1960 in primary monkey kidney cell cultures being used to grow Sabin OPV. ==Regions== The genome is functionally divided into 3 regions: # Early: Expressed early in virus infection, i.e. BEFORE genome replication. Expression of early genes continues during the late stage of infection. Encodes non-structural proteins (i.e. not present in virus particle). # Late: Expressed later in virus infection, i.e. DURING & AFTER genome replication. Encodes structural proteins (i.e. present in virus particle). # Regulatory region: Contains transcriptional promoters & enhancers plus the unique origin of DNA replication. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「SV40 large T antigen」の詳細全文を読む スポンサード リンク
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