Isolation and properties of rex - mutants of bacteriophage lambda.

Twenty-five rex(-) mutants of phage lambda have been isolated. Three of the mutants, including one amber mutant, map at three distinct sites within the rex region of the lambda genetic map. The existence of the amber mutant provides further evidence that rex and cI are distinct genes, since it seems to be identical to wild-type lambda in its ability to establish or maintain lysogeny.