A MINIMAL SET OF RNA-POLYMERASE-II TRANSCRIPTION PROTEIN INTERACTIONS

All pairwise interactions of RNA polymerase II and general transcripti on factors (TF) IIB, E, F, and H have been quantitated by surface plas mon resonance with the use of a Ni2+ chelate on the sensor surface whe re necessary to attain higher sensitivity. Only 4 of 10 possible inter actions were found above the detection limit: TFIIB, -E, and -F bindin g RNA polymerase II and TFIIE binding to TFIIH. These four interaction s constitute a minimal set for the formation of a transcription initia tion complex and may represent the primary interactions involved in as sembly of the complex. Point mutations in TFIIB that alter the locatio n of transcription start sites in vivo markedly diminished the affinit y of TFIIB binding to RNA polymerase II. Protein blotting revealed an interaction between the largest subunit of TFIIE and third largest sub unit of TFIIH, which may be responsible for the TFIIE binding to TFIIH .