Transrepression of RNA polymerase II promoters by the simian virus 40 small t antigen.
Simian virus 40 (SV40) small t antigen (t) can activate transcription from certain RNA polymerase II and III promoters (M. Loeken, I. Bikel, D. M. Livingston, and J. Brady, Cell 55:1171-1177, 1988). Here we report a new function of t, its ability to repress human c-fos promoter and AP-1 transcriptional activity in CV-1P cells. This function is the product of a discrete N-terminal domain of t, because the large T antigen (T)/t-common polypeptide, which contains only the first 82 amino acids common to both T and t of SV40, was, like the intact protein, an active repressor. The data further suggest that the t- and T/t-common-mediated repression of c-fos expression was most likely manifest at the level of transcription. In keeping with the possibility that t affects the expression of the genomic c-fos promoter, it also led to repression of AP-1 formation. Thus, SV40 is both an activator and a repressor of transcription. Its ability to inhibit c-fos expression should be considered in light of the natural history of SV40 in its natural host.
Wang
W B
WB
Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Bikel
I
I
Marsilio
E
E
Newsome
D
D
Livingston
D M
DM
D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism*; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D002522:Chlorocebus aethiops; D004742:Enhancer Elements, Genetic; D015870:Gene Expression; D016762:Genes, fos; D013006:Growth Hormone / Q000096:biosynthesis; D006801:Humans; D007668:Kidney; D011401:Promoter Regions, Genetic; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D016755:Proto-Oncogene Proteins c-jun / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D012319:RNA Polymerase II / Q000096:biosynthesis*; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D013539:Simian virus 40 / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection
D000952:Antigens, Polyomavirus Transforming; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D013006:Growth Hormone; D015500:Chloramphenicol O-Acetyltransferase; D012319:RNA Polymerase II