Coates N J, Dibbens J A, Moffat K G, Egan J B
Department of Biochemistry, University of Adelaide, Australia.
Mutat Res. 1998 Aug 7;408(2):147-57. doi: 10.1016/s0921-8777(98)00027-5.
The oriC transducing phage lambda poriCc is a pseudovirulent phage capable of forming plaques on a lambda lysogen. This phenotype is dependent upon the presence of the oriC insert. The ability of lambda poriCc to form plaques on a lambda lysogen represents a potential phage assay system for studying aspects of oriC function. In the present study we establish that lambda poriCc infection of a lambda lysogen is a legitimate assay for oriC function. We use this assay to confirm the previously reported observation that initiation of DNA replication from oriC is transiently inhibited in a ultra violet (UV) irradiated cell at doses greater than 60 J/m2. We further demonstrate using this assay that the UV induced inhibition of initiation of DNA replication from oriC is not a SOS function nor a heat shock function. In the course of these studies, we found that lambda poriCc infection of a non-lysogenic cell is extremely sensitive to pre-irradiation of the Escherichia coli host. We postulate that the sensitivity of lambda poriCc replication to host cell pre-irradiation reflects in some way the transient inhibition of initiation of DNA replication from oriC following UV irradiation.
