Wonderling Laura D, Urbanowski Mark L, Stauffer George V
Department of Microbiology, The University of Iowa, Iowa City, IA 52242, USA1.
Microbiology (Reading). 2000 Nov;146 ( Pt 11):2909-2918. doi: 10.1099/00221287-146-11-2909.
GcvA binds to three sites in the gcvTHP control region, from base -34 to -69 (site 1), from base -214 to -241 (site 2) and from base -242 to -271 (site 3). Previous results suggested that sites 3 and 2 are required for both GcvA-dependent activation and repression of a gcvT::lacZ fusion. However, the results were less clear as to the role of site 1. To determine the role of site 1 in regulation, single and multiple base changes were made in site 1 and tested for their ability to alter GcvA-mediated activation and GcvA/GcvR-mediated repression. Several of the mutants were also tested for effects on GcvA binding to site 1 and the ability of GcvA to bend DNA at site 1. The results are consistent with site 1 playing primarily a role in negative regulation of the gcvTHP operon.
