Cooperative DNA binding by CI repressor is dispensable in a phage lambda variant.

ABSTRACT: Complex gene regulatory circuits contain many interacting components. In principle, all of these components and interactions may be essential to the function of the circuit. Alternatively, some of them may be refinements to a simpler version of the circuit that improve its fitness. In this work, we have tested whether a particular property of a critical regulatory protein, CI, is essential to the behavior of the phage lambda regulatory circuit. In the lysogenic state, CI represses the expression of the lytic genes, allowing a stable lysogenic state, by binding cooperatively to six operators. A mutant phage lacking cooperativity because of a change in cI could not form stable lysogens; however, this defect could be suppressed by the addition of mutations that altered two cis-acting sites bu

SUBMITTER: Babic AC 

PROVIDER: S-EPMC2077068 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature