Genetic information of the bacteriocinogenic plasmid Clo DF13 involved in the inhibition of the multiplication of double stranded DNA phages.

The presence of plasmid Clo DF13 in Escherichia coli cells alters the response of these cells to infection with the double stranded DNA phages P1vir, lambda vir or T1. The multiplication of these phages is reduced in Clo DF13 harbouring cells, resulting in an altered burstsize and plaque morphology. The degree of reduction is correlated to the amount of particular Clo DF13 gene product(s) in the cell. The genetic information of Clo DF13 involved in this plasmid-phage interaction could be located, using insertion and deletion mutants of Clo DF13, between 29 an 62% on the Clo DF13 physical map. The genetic analysis of this region shows that at least two different genes, K and L, coding for polypeptides with a molecular weight of respectively 21 KD and 10.5 KD, are located in this region. The results presented, indicate that gene L and not gene K is involved in the interaction of Clo DF13 with the propagation of double stranded DNA phages.