CHARACTERIZATION OF BACTERIOPHAGE-P1 DNA FRAGMENTS CLONED IN A LAMBDA-VECTOR

Seventeen of the twenty-six possible EcoRI-generated fragments of P1 DNA have been cloned in a λD-srIλ3 vector. The results of marker rescue experiments with these λ-P1 hybrid phages reveal a clustering of P1 am mutations on the P1 DNA and a localization to a small part of that DNA of P1 functions involved in plasmid replication and plasmid segregation fidelity. Various elements of the complex P1 immunity system have been mapped to particular P1 fragments located in three separate regions of the P1 genome. Hybrid phages that express the P1 ban gene and P1 modification (mod) gene have also been isolated. The recombinant phages described in this paper constitute a set of tools with which to define the role of particular segments of the P1 genome in the physiology of this organism. © 1979.