Independent expression of the transforming amino-terminal domain of SV40 large I antigen from an alternatively spliced third SV40 early mRNA.
We found that simian virus 40 (SV40), in addition to the SV40 early proteins large T antigen (large T) and small antigen (small t), codes for a third early protein with a molecular weight of 17 kDa. This protein (17kT) is expressed from an alternatively spliced third SV40 early mRNA, using a splice donor site at position 4425 and a splice acceptor site at position 3679 of the SV40 genome. The 17kT protein consists of 135 amino acids. Of these, 131 correspond to the amino-terminus of large T, while the four carboxy-terminal amino acids are unique and encoded by a different reading frame. 17kT mRNA, and the corresponding protein, were found in all SV40 transformed cells analyzed, as well as in SV40 infected cells. Transfection of a cDNA expression vector encoding the 17kT protein into rat F111 fibroblasts induced phenotypic transformation of these cells. The expression of the transforming amino-terminal domain of large T as an independent 17kT protein might provide a means for individually regulating the various functions associated with this domain.
Zerrahn
J
J
Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie, Universität Hamburg, Germany.
Knippschild
U
U
Winkler
T
T
Deppert
W
W
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D001483:Base Sequence; D015152:Blotting, Northern; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D004279:DNA, Viral; D008969:Molecular Sequence Data; D010641:Phenotype; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D051381:Rats; D013539:Simian virus 40 / Q000235:genetics*; D014162:Transfection
D000952:Antigens, Polyomavirus Transforming; D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral