An SV40 large T antigen binding site in the cellular genome is part of a cis-acting transcriptional element.
A genomic mouse DNA fragment (Q300), containing a high affinity binding site for SV40 large T antigen, serves as a cis-acting transcriptional element in in vivo and in in vitro studies. We have performed experiments to investigate whether bound T antigen could modulate the promoter-enhancer activity of the Q300 element. In vivo studies showed a negative effect of T antigen on the Q300 driven expression of the chloramphenicol acetyl transferase reporter gene. Band shift and DNAase I protection experiments demonstrated that T antigen and a nuclear protein, probably a CCAAT-binding factor, can simultaneously bind to closely adjacent sites on the Q300 DNA. Transcription studies in vitro showed that bound T antigen suppresses the transcriptional enhancer effect of the Q300 element. We interpret the results of these model studies to indicate that T antigen, bound to DNA, is able to affect the function of a cellular cis-acting transcriptional element. Bound T antigen may influence the activity of a cellular transcription factor at a closely adjacent DNA site.
Wagner
S
S
Fakultät für Biologie, Universität Konstanz, Federal Republic of Germany.
Knippers
R
R
D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D015183:Restriction Mapping; D013539:Simian virus 40 / Q000276:immunology*; D013698:Templates, Genetic; D014158:Transcription, Genetic; D014162:Transfection
D000952:Antigens, Polyomavirus Transforming; D004247:DNA