Fourteen frameshift mutants of bacteriophage P22 have been isolated following mutagenesis by ICR-191. These mutants can grow only in hosts carrying a frameshift suppressor. Two of the mutants will grow on strains carrying sufA, the most efficient of the three suppressors which read the four base codon CCC·. Twelve other phage mutants can grow only in strains carrying the sufD suppressor, which reads the codon GGG·. The fourteen frameshift mutations map at eight sites in the P22 genetic map. Only five P22 genes are affected: 12, 23, 2, 10 and 9. The non-random distribution of sites may be due to hot spots for frameshift mutagenesis. The low efficiency of frameshift suppressors may limit detectable frameshift mutations to genes for which a low product level still permits plaque formation.
ASJC Scopus subject areas