Bacteriophage T4 MotA and AsiA proteins suffice to direct Escherichia coli RNA polymerase to initiate transcription at T4 middle promoters.

AUTOR(ES)

Ouhammouch, M

RESUMO

Development of bacteriophage T4 in Escherichia coli requires the sequential recognition of three classes of promoters: early, middle, and late. Recognition of middle promoters is known to require the motA gene product, a protein that binds specifically to the "Mot box" located at the -30 region of these promoters. In vivo, the asiA gene product is as critical for middle mode RNA synthesis as is that of the motA gene. In vitro, AsiA protein is known to loosen the sigma 70-core RNA polymerase interactions and to inhibit some sigma 70-dependent transcription, presumably through binding to the sigma 70 subunit. Here we show that, in vitro, purified MotA and AsiA proteins are both necessary and sufficient to activate transcription initiation at T4 middle promoters by the E. coli RNA polymerase in a sigma 70-dependent manner. AsiA is also shown to inhibit recognition of T4 early promoters and may play a pivotal role in the recognition of all three classes of phage promoters.

Documentos Relacionados

• Stimulation of bacteriophage T4 middle transcription by the T4 proteins MotA and AsiA occurs at two distinct steps in the transcription cycle
• Substitutions in Bacteriophage T4 AsiA and Escherichia coli ς70 That Suppress T4 motA Activation Mutations
• The Bacteriophage T4 Transcription Activator MotA Interacts with the Far-C-Terminal Region of the σ70 Subunit of Escherichia coli RNA Polymerase
• The asiA gene product of bacteriophage T4 is required for middle mode RNA synthesis.
• The asiA Gene Product of Bacteriophage T4 Is Required for Middle Mode RNA Synthesis