The Escherichia coli RNA polymerase alpha subunit and transcriptional activation by bacteriophage lambda CII protein.
Bacteriophage lambda is not able to lysogenise the Escherichia coli rpoA341 mutant. This mutation causes a single amino acid substitution Lys271Glu in the C-terminal domain of the RNA polymerase alpha subunit (alphaCTD). Our previous studies indicated that the impaired lysogenisation of the rpoA341 host is due to a defect in transcriptional activation by the phage CII protein and suggested a role for alphaCTD in this process. Here we used a series of truncation and point mutants in the rpoA gene placed on a plasmid to investigate the process of transcriptional activation by the cII gene product. Our results indicate that amino-acid residues 265, 268 and 271 in the a subunit may play an important role in the CII-mediated activation of the pE promoter (most probably residue 271) or may be involved in putative interactions between alphaCTD and an UP-like element near pE (most probably residues 265 and 268). Measurement of the activity of pE-lacZ, pI-lacZ and p(aQ)-lacZ fusions in the rpoA+ and rpoA341 hosts demonstrated that the mechanism of activation of these CII-dependent promoters may be in each case different.
Department of Molecular Biology, University of Gdańsk, Poland.
M
M
Gabig
M
M
Obuchowski
A
A
Ciesielska
B
B
Latała
A
A
Wegrzyn
M S
MS
Thomas
G
G
Wegrzyn
D019677:Artificial Gene Fusion; D010582:Bacteriophage lambda / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D007763:Lac Operon; D008242:Lysogeny; D010446:Peptide Fragments / Q000235:genetics*; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014764:Viral Proteins
D010446:Peptide Fragments; D014157:Transcription Factors; D014764:Viral Proteins; C039000:cII protein, bacteriophage lambda; D012321:DNA-Directed RNA Polymerases