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Subclasses of simian virus 40 large T antigen: differential binding of two subclasses of T antigen from productively infected cells to viral and cellular DNA.
Author(s) -
Fanning E.,
Westphal K.H.,
Brauer D.,
Cörlin D.
Publication year - 1982
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1982.tb01290.x
Subject(s) - biology , antigen , virology , simian , virus , dna , microbiology and biotechnology , immunology , genetics
Two major subclasses of simian virus 40 (SV40) large T antigen were separated by zone velocity sedimentation of crude extracts from productively infected cells. These subclasses, which have been shown to differ biologically and biochemically (Fanning et al., 1981), sedimented at 5‐6S and 14‐16S. The amount of T antigen in each form was estimated by complement fixation and by immunoprecipitation of T antigen from extracts of cells chronically labeled with [35S]methionine. Each form of T antigen was tested for specific binding to end‐labeled restriction fragments of SV40 DNA using an immunoprecipitation assay. The 5‐6S and 14‐16S forms of T antigen both bound specifically to DNA sequences in the SV40 HindIII C fragment. The sequences required for binding both forms were localized in the same 35‐bp region of the origin. However, significant differences in binding activity and affinity for specific and nonspecific DNA were demonstrated. These properties suggest that T antigen subclasses may serve different functions in the lytically infected cell.