Gene 24-controlled osmotic shock resistance in bacteriophage T4: probable multiple gene functions.

By use of mixed infections with conditional lethal mutations in the head genes and an osmotic shock-resistant mutant it has been demonstrated that osmotic shock resistance is controlled by gene 24. Using acrylamide gel electrophoresis combined with the immune replicate technique confirmed the positions of gene products 24 and 24* (P24 and P24*). The notation P24, etc., is used for designating the product of gene 23, etc., although is preferred the designation gp23 as introduced by Casjens and King is preferred. The reason for using the old notation is because the illustrations were prepared several years ago.) P24 ts showed a significantly slower mobility. Both osmotic shock-resistant and -sensitive mature phages contain 24*. Giants constructed with the Os/sup r/ phage showed the same surface lattice as normal phage. Through temperature-shift experiments with 24(tsL90) alone and in combinations the phages which are matured after the shift to permissive temperature in the absence of new protein synthesis was studied. Results strongly suggest that only a fraction of the total phage complement of gene 24-controlled proteins is involved in determining the phenotype of shock resistance, and the remainder is necessary to mature the head.