Ant-mediated inactivation of Salmonella phage L-specified repression at OR of prophage L

Ant product of phage P22 inactivates repression of prophage L at the right-hand operator OR and allows for transactivation of prophage gene 12. The transactivation efficiency observed with a series of phage and prophage recombinants, using single superinfection of a lysogenic bacterium, is about the same as that recently observed at OL of prophage L. This finding is in contrast to the failure to demonstrate derepression at OR of prophage L in an experimental system employing double superinfection (Prell, 1978a). The reasons for the differing results are discussed and it is shown that derepression by the ant product in trans at OR of the prophage is not modified to any significant degree by the immunity specificity (L or p22) of the prophage or of the superinfecting phage.