This promoter/repressor pair originates from Lambda phage. Employing either a lytic or lysogenic life cycle, this bacteriophage infects it's E. coli host with double stranded DNA. cI binds at OR1, OR2 and OR3 sites with preference given to the OR1 site.

cI Lambda

Construct

Mutant Screening

We selected mutants by first visually picking colonies from transformation plates. From there we used our plate reader to read the GFP fluorescence of each mutant on a 96 well screening plate. In the graph above, the green bars represent mutant expression that is 1.5 standard deviations from the average wildtype fluorescence. Many of our mutants show very low to no expression which indicates that the error-prone pcr which produced them was notably mutagenic. We found 9 suitable candidates to further characterize using the process outlined in the Data page.