Kinetics of c2-repressor synthesis in a regulatory defective P22 mutant

Phage P22 defective in gene 24 and harbouring the Oc mutation k5 in OR exhibits a strongly increased c2-repressor synthesis after infection of non-lysogenic S. typhimurium. The repressor synthesis depends strictly on an intact c1 gene. The kinetics of its synthesis, as monitored by polyacrylamide gel electrophoresis, is the same as with P22 c+, namely a turn off 8-10 min after infection. - After infection of P22-lysogenic bacteria with either P22 24- k5 or P22 24- k5 c1, much lower amounts of repressor are synthesized but again with the same kinetics. These results suggest a cro-like function acting at PRE and PRM of P22. The possible reason for the c2 overproduction is discussed.