Birth Rate Increases following Improved Rural Water Supply

The bacteriophage j pM promoter is required for maintenance of the j prophage in Escherichia coli, as it facilitates transcription of the cI gene, encoding the j repressor (CI). CI levels are maintained through a transcriptional feedback mechanism whereby CI can serve as an activator or a repressor of pM. CI activates pM through cooperative binding to the OR1 and OR2 sites within the OR operator, with the OR2-bound CI dimer making contact with domain 4 of the RNA polymerase p subunit (p4). Here we demonstrate that the 261 and 287 determinants of the C-terminal domain of the RNA polymerase a subunit (aCTD), as well as the DNA-binding determinant, are important for CI-dependent activation of pM. We also show that the location of aCTD at the pM promoter changes in the presence of CI. Thus, in the absence of CI, one aCTD is located on the DNA at position 44 relative to the transcription start site, whereas in the presence of CI, aCTD is located at position 54, between the CI-binding sites at OR1 and OR2. These results suggest that contacts between CI and both aCTD and p are required for efficient CI-dependent activation