J R Scott

Genetic studies on bacteriophage P1

Abstract Conditional lethal mutants that fall into 18 different cistrons have been defined, and the relative order of some of them has been established. Mutants affecting ability to lysogenize (clear mutants), including a virulent mutant, define five more cistrons. Unlike those of other temperate phages, the clear mutants of P1 do not map together in a small region.

A defective P1 prophage with a chromosomal location

Abstract Phage P1 cryptic, isolated from P1dCM, is defective and carries the genes for chloramphenicol resistance. Many of the known P1 genes have been deleted from P1cry and these are all contiguous with the exception of one mutant. Although gene c1+ (the immunity repressor gene) can be rescued from P1 cryptic lysogens by all known c1 mutants, cryptic lysogens are not immune. P1 cryptic was found to be located on the host chromosome between lac and pro, and it provides a region of attachment at which a superinfecting wild-type P1 can enter the host chromosome.