Activation of Bacteriophage Mu mom Transcription by C Protein Does Not Require Specific Interaction with the Carboxyl-Terminal Region of the α or ς(70) Subunit of Escherichia coli RNA Polymerase

Late in its growth cycle, transcription of the phage Mu mom promoter (P(mom)) is activated by the phage gene product, C, a site-specific DNA binding protein. In vitro transcription analyses showed that this activation does not require specific contacts between C and the carboxyl-terminal region of the α or ς(70) subunit of Escherichia coli RNA polymerase. Unexpectedly, these results are in contrast to those known for another Mu-encoded transcriptional activator, Mor, which has a high degree of sequence identity with C and appears to interact with the carboxyl termini of both α and ς(70).