DNA topoisomerase I is involved in both repression and activation of transcription.
Reconstituted transcription reactions containing the seven general transcription factors, in addition to RNA polymerase II, respond poorly to transcriptional activators. Two factors, Dr2 and ACF, necessary for high levels of transcription in response to an activator have been identified. ACF can enhance basal and activated transcription. Dr2 represses basal transcription, but this can be overcome by transcriptional activators or TFIIA. Dr2 is human DNA topoisomerase I. The DNA relaxation activity of topoisomerase I is dispensable for transcriptional repression. The effect of Dr2 is specific for TATA-box-containing promoters and is mediated by the TATA-binding protein.
Merino
A
A
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5635.
Madden
K R
KR
Lane
W S
WS
Champoux
J J
JJ
Reinberg
D
D
D000595:Amino Acid Sequence; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004270:DNA, Circular / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D016385:TATA Box; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D004270:DNA, Circular; D011994:Recombinant Proteins; D012097:Repressor Proteins; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D012319:RNA Polymerase II; D004264:DNA Topoisomerases, Type I