Isolation of P22 specialized transducing phage followong F'-episome fusion

A P22 specialized transducing phage has been constructed which carries the structural gene for aspartate transcarbamylase (ATCase). This gene (pyrB) was first brought close to the P22 attachment site by fusing an F' pyrB(+) episome to an F' prolac episome which carries a P22 prophage attachment site. A prophage was added to these fused F' episomes and the lysogen was UV-induced. The specialized transducing phage was isolated from the resulting lysate. The phage also carries argI, the structure gene for ornithine transcarbamylase.