Bacteriophage P2: Genes Involved in Baseplate Assembly

The sequences of two previously defined tail genes, V and J, of the temperate bacteriophage P2, and those of two new essential tail genes, W and I, were determined. Their order is the late gene promoter, VWJI, followed by the tail fiber genes H and G, and a transcription terminator. The V gene product is the small spike at the tip of the tail, and the J gene product lies at the edge of the baseplate. The W gene product may be homologous to the product of gene 25 of T4 phage, which is part of the T4 baseplate. A temperature-sensitive mutation in gene V affects satellite phage P4 production more than it affects the production of P2 helper phage. P4 mutations that partially compensate for this defect of gene V lie in the P4 capsid size determination gene, sid.