Stahl H, Bauer M, Knippers R
Eur J Biochem. 1983 Jul 15;134(1):55-61. doi: 10.1111/j.1432-1033.1983.tb07530.x.
The large tumor antigen (T antigen) is a genome regulation protein, coded by simian virus 40, that binds with high affinity to specific binding sites on viral DNA. The specifically bound T antigen is released from these sites in 0.2-0.3 M NaCl. Immunoprecipitation techniques were used to show that T antigen also dissociates in 0.2-0.3 M NaCl from mature viral chromatin but not from replicating viral chromatin. In fact, a considerable fraction of T antigen remains associated with replicating chromatin at NaCl concentrations as high as 1.2 M NaCl when most chromatin proteins, including histones, dissociate. However, T antigen binding to both replicating DNA and mature DNA is sensitive to intercalating drugs such as caffeine and ethidium bromide. We consider the possibility that the unexpectedly tight binding of T antigen to replicating DNA is related to the function that T antigen performs during viral DNA replication.
大肿瘤抗原（T抗原）是一种由猴病毒40编码的基因组调节蛋白，它能与病毒DNA上的特定结合位点高亲和力结合。在0.2 - 0.3M NaCl中，特异性结合的T抗原会从这些位点释放出来。免疫沉淀技术表明，T抗原在0.2 - 0.3M NaCl中也会从成熟病毒染色质上解离，但不会从正在复制的病毒染色质上解离。实际上，当包括组蛋白在内的大多数染色质蛋白解离时，在高达1.2M NaCl的浓度下，相当一部分T抗原仍与正在复制的染色质结合。然而，T抗原与正在复制的DNA和成熟DNA的结合对咖啡因和溴化乙锭等嵌入药物敏感。我们考虑了T抗原与正在复制的DNA意外紧密结合可能与T抗原在病毒DNA复制过程中所执行的功能有关这一可能性。
