Specificity of polarity suppression in E. coli: correction of defects in gene N, but not in gene Q, of phage lambda.

The bacterial mutation psuA1, known as (suA) a polarity suppressor, partially relieves all N defects in bacteriophage lambda growth. No evidence is found that psuA1 relieves Q defects in lambda growth. Specific mechanisms of action by the N and Q gene products are discussed. The psuA1 mutation was also found to suppress IS1 type but not IS2 type insertion mutations in lambda.