期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1981
卷号：78
期号：1
页码：105-109
DOI：10.1073/pnas.78.1.105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Simian virus 40 large tumor antigen (T Ag) can be separated by sucrose gradient sedimentation into a rapidly sedimenting, maximally phosphorylated fraction and a slowly sedimenting, less phosphorylated fraction. The Mr 48,000 host tumor antigen (48,000 HTA, also called nonviral T Ag) is preferentially complexed with the maximally phosphorylated T Ag. Pulse-labeled T Ag sediments as a 5-6S monomer, whereas T Ag radiolabeled for progressively longer periods slowly increases in sedimentation coefficient to give a broad distribution between 5 S and greater than 28 S. Mutation in the viral A locus causes a decrease in T Ag phosphorylation and a marked decrease in 48,000 HTA binding, shifting the sedimentation coefficient of T Ag to the monomer value. The more highly phosphorylated T Ag also has the highest affinity for chromatin.
