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

Summary Phage P22 defective in gene 24 and harbouring the o^c mutation k5 in O_R 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 polyacrylamid 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 cl, much lower amounts of repressor are synthesized but again with the same kinetics. These results suggest a cro-like function acting at P_RE and P_RM of P22. The possible reason for the c2 overproduction is discussed.