Factors involved in specific transcription by mammalian RNA polymerase II: identification of general transcription factor TFIIG.
We have identified and partially characterized another human general transcription factor, TFIIG. Using a reconstituted in vitro system comprised of purified RNA polymerase II, TFIIB, TFIID, TFIIE, and TFIIF, we found that TFIIG was essential for specific initiation from all class II genes tested. In this system TFIIA could partially replace TFIIG; however, even at saturating concentrations of TFIIA, addition of TFIIG further stimulated transcription. Since the chromatographic properties of TFIIG differed significantly from those of TFIIA, we concluded that TFIIA and TFIIG are distinct but functionally related transcription factors. Heparin challenge assays showed that TFIIG is required for the assembly of a functional preinitiation complex. However, it must act after template commitment by TFIID, since this step did not require, and was unaffected by, either TFIIG or TFIIA.
Sumimoto
H
H
Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, NY 10021.
Ohkuma
Y
Y
Yamamoto
T
T
Horikoshi
M
M
Roeder
R G
RG
D002467:Cell Nucleus / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006367:HeLa Cells / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D012319:RNA Polymerase II / Q000378:metabolism*; D013698:Templates, Genetic; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic / Q000187:drug effects
D014157:Transcription Factors; D019473:Transcription Factors, TFII; C066643:transcription factor TFIIG; D006493:Heparin; D012319:RNA Polymerase II