title: Purification of biologically active simian virus 40 small tumor antigen.
abstract: The simian virus 40 small tumor antigen (t antigen) gene has been cloned downstream from a hybrid Escherichia coli trp-lac promoter and a suitable ribosome binding site. A bacterial clone (865i) transformed by such a plasmid (pTR865) expresses this gene and, under optimal conditions, can produce greater than or equal to 5% of its total protein as t antigen. Soluble extracts of such a clone were relatively depleted in t antigen, which was found in the initial pellet fraction. The protein was recovered from this fraction in a significantly purified form by extraction with urea-containing buffer. After gel filtration of such t antigen-enriched solutions, highly purified protein was obtained. When either this fraction (freed of urea) or NaDodSO4 gel-purified 865i t antigen (rendered free of detergent) was injected into untransformed rat cells, dissolution of intracellular actin cable networks was observed.
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000302:isolation & purification*; D000957:Antigens, Viral, Tumor; D002472:Cell Transformation, Viral; D003001:Cloning, Molecular; D003599:Cytoskeleton / Q000648:ultrastructure; D004926:Escherichia coli / Q000235:genetics; D008970:Molecular Weight; D051381:Rats; D013539:Simian virus 40 / Q000276:immunology*
chemical_list: D000956:Antigens, Viral; D000957:Antigens, Viral, Tumor