ENHANCEMENT OF BACTERIAL TRANSCRIPTION INITIATION IN-VITRO BY THE 74-KDA SUBUNIT OF HUMAN GENERAL TRANSCRIPTION FACTOR-IIF (RAP74)

The human general transcription factor IIF (TFIIF) is required for an accurate transcription initiation by RNA polymerase II and shares some analogous features with the sigma subunit of bacterial RNA polymerase . As an attempt to analyze the function of TFIIF, we examined its effe ct on bacterial transcription in vitro. TFIIF significantly enhanced t he initiation of transcription by the bacterial RNA polymerase while o ther general transcription factors, TATA-binding protein, TFIIB, and T FIIE, did not. The enhancement of the bacterial transcription was ascr ibed to the 74 kDa subunit of TFIIF (RAP74). RAP74 had an activity of enhancing the binding of the bacterial RNA polymerase to the promoter. The enhancing activity of RAP74 depended on a low molar ratio of the RNA polymerase to the template DNA. The action of RAP74 in the bacteri al transcription may be related to a possible regulatory role of RAP74 in the eukaryotic transcription initiation.