Negative supercoiling of DNA facilitates an interaction between transcription factor IID and the fibroin gene promoter.
Transcription of the fibroin gene can be reconstituted with partially purified components from HeLa cells. Transcription factors IIB, IID, and IIE and RNA polymerase II are required for accurate initiation of transcription. Linear and relaxed closed circular DNA show a similar level of template activity. However, transcription of closed circular DNA is stimulated when negative supercoils are introduced by the addition of DNA topoisomerase II and supercoiling factor purified from the posterior silk gland of Bombyx mori. Dissection of transcription into pre- and postinitiation steps by the use of Sarkosyl reveals that DNA supercoiling promotes formation of a preinitiation complex. Furthermore, order of addition experiments suggest that DNA supercoiling facilitates a functional binding of transcription factor IID to the promoter.
Mizutani
M
M
DNA Research Center, National Institute of Genetics, Mishima, Japan.
Ohta
T
T
Watanabe
H
H
Handa
H
H
Hirose
S
S
D002467:Cell Nucleus / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism*; D005349:Fibroins / Q000235:genetics*; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic
D004278:DNA, Superhelical; D011994:Recombinant Proteins; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D005349:Fibroins