Isolation and some properties of bacteriophage alpha3 gene J mutant.

To elucidate the in vivo function of the J gene of microvirid (isometric) phages, we isolated several strains carrying a double mutation in J and H genes from phage alpha3 and then constructed single mutants each having an amber codon in the J gene. The J mutants could not multiply in suppressor-less hosts and were deficient in single-stranded progeny DNA synthesis. Nucleotide sequences of the wild-type and mutant alpha# J genes were analyzed to determine the mutation sites. The amino acid sequence of the J gene was also deduced from the nucleotide sequence and compared with those of phiX174 and G4.