DRASTICALLY DECREASED TRANSCRIPTION FROM CII-ACTIVATED PROMOTERS IS RESPONSIBLE FOR IMPAIRED LYSOGENIZATION OF THE ESCHERICHIA-COLI RPOA341MUTANT BY BACTERIOPHAGE-LAMBDA

It was demonstrated previously that a mutation, rpoA341, in the gene e ncoding the a subunit of Escherichia coli RNA polymerase prevents lyso genization by bacteriophage lambda. The rpoA341 allele is known to be responsible for impaired transcription of some positively regulated E. coli chromosomal operons. Here we demonstrate that the inhibition of lysogenization of the rpoA341 mutant is a result of drastically decrea sed transcription from positively regulated phage promoters. We were u nable to detect any transcripts originating from the CII-activated p(E ), p(I) and p(aQ) promoters (important for lysogenic development) iq t he phage-infected rpoA341 mutant, in contrast to an otherwise isogenic rpoA(+) strain. The results are discussed in the light of other repor ts showing that activation of the p(E) promoter by CII protein in vitr o is decreased only about fivefold when the native alpha subunit is re placed by truncated alpha polypeptides.