title: Recombinant P4 bacteriophages propagate as viable lytic phages or as autonomous plasmids in Klebsiella pneumoniae.
abstract: We demonstrate the use of bacteriophage P4 as a molecular cloning vector in Klebsiella pneumoniae. A hybrid P4 phage, constructed in vitro, that contains a K. pneumoniae hisDG DNA fragment can be propagated either as a lytic viable specialized transducing phage or as an autonomous, self-replicating plasmid. Hybrid P4 genomes existing as plasmids can be readily converted into non-defective P4-hybrid phage particles by superinfection with helper phage P2. Infection of a K. pneumoniae hisD non-P2 lysogen with P4-hisD hybrid phage results in approximately 90% of the infected cells becoming stably transduced to HisD+. Because P4 interferes with P2 growth, high titre stocks of P4 hybrid phages are relatively free (less than or equal to 10(-6) of P2 contamination. The hisG gene product was detected in ultraviolet light irradiated host cells infected by the P4-hisDG hybrid phage. A mutant of P4 (P4sid1) that directs the packaging of P4 DNA into P2 sized capsids should permit the construction of hybrid phages carrying 26 kilobase inserts.
mesh_terms: D001435:Bacteriophages / Q000235:genetics*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics*; D005796:Genes; D005822:Genetic Vectors; D006639:Histidine / Q000235:genetics; D007711:Klebsiella pneumoniae / Q000235:genetics*; D009154:Mutation; D010957:Plasmids
chemical_list: D004269:DNA, Bacterial; D006639:Histidine