Overproduction of phage lambda repressor under control of the lac promotor of Escherichia coli.

The gene coding for bacteriophage Lambda repressor (cI gene) has been fused to the lac operon of Escherichia coli. In some of the fusions Lambda repressor synthesis can be controlled by the lac operator and promoter. Upon induction of the lac operon the amount of Lambda repressor is increased by a factor of 7 over that found in a single lysogen. In combination with the polarity suppressor suA the induction factor rises to 20. Transducing phages of one fusion were constructed. After thermal induction of this phage the final level of Lambda repressor was enhanced by a factor of 150.