title: Large and small tumor antigens from simian virus 40 have identical amino termini mapping at 0.65 map units.
abstract: Large and small tumor (T)antigens of simian virus 40 were synthesized in vitro with L-cell extracts that had been treated by the method of Palmiter to prevent amino-terminal acetylation of nascent proteins. Partial amino-terminal amino acid sequences of both forms of T-antigen were determined and found to be identical. Methionine residues were located at positions 1 and 14, a lysine residue at position 3, and leucine residues at positions 5, 11, 13,16, 17, and 19. These amino acid sequence data match perfectly the amino acid sequence predicted from a sequence of nucleotides in the E strand of simian virus 40 DNA which begins near the junction between HindII/III fragments A and C at about 0.65 map units. This strongly suggests that the sequence coding for the amino terminus of both proteins is located at this position. Furthermore, the data are consistent with a model for the synthesis of both forms of T-antigen that predicts that (i) small T-antigen is coded for by a sequence of nucleotides from the 5' end of the early region and (ii) large T-antigen is coded for by nucleotide sequences from two noncontiguous regions of simian virus 40 DNA.
mesh_terms: D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000235:genetics; D000956:Antigens, Viral / Q000235:genetics; D002874:Chromosome Mapping; D008970:Molecular Weight; D013539:Simian virus 40 / Q000235:genetics / Q000276:immunology*; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D014764:Viral Proteins