Bacteriophage T4 MotA and AsiA proteins suffice to direct Escherichia coli RNA polymerase to initiate transcription at T4 middle promoters.
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.
Ouhammouch
M
M
State University of New York, Department of Biological Sciences, Buffalo 14260.
Adelman
K
K
Harvey
S R
SR
Orsini
G
G
Brody
E N
EN
D017122:Bacteriophage T4 / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000502:physiology*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D066298:In Vitro Techniques; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins; D012808:Sigma Factor / Q000378:metabolism; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000502:physiology*; D015678:Viral Structural Proteins / Q000235:genetics
C078876:AsiA protein, Enterobacteria phage T4; D004268:DNA-Binding Proteins; C067996:MotA protein, Enterobacteria phage T4; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012808:Sigma Factor; D014157:Transcription Factors; D014764:Viral Proteins; D015678:Viral Structural Proteins; D012321:DNA-Directed RNA Polymerases