PROMOTER OPENING (MELTING) AND TRANSCRIPTION INITIATION BY RNA POLYMERASE-I REQUIRES NEITHER NUCLEOTIDE-BETA,GAMMA HYDROLYSIS NOR PROTEIN-PHOSPHORYLATION

With some bacterial RNA polymerases and in eukaryotic RNA polymerase I I, DNA melting during initiation requires the coupling of energy deriv ed from beta,gamma hydrolysis of ATP. A detailed analysis of this poss ible requirement for eukaryotic RNA polymerase I reveals no such requi rement. However, in some cases, beta,gamma non-hydrolyzable derivative s (beta,gamma imido or methylene) of nucleotide substrates have been f ound to significantly inhibit transcription initiation because of thei r inefficient use as the first nucleotide of the transcript. In additi on, the results presented here show that protein kinase activity is no t required as an integral part of transcription initiation by RNA poly merase I. Prior phosphorylation of proteins participating in the proce ss is not ruled out.