Organization of the bacteriophage T4 tail fiber gene cluster 34-38

A correlation of the genetic, functional, and structural maps of the T4 tail fiber gene cluster has been achieved by analysis of lambda derivatives carrying genes 34-38. 31 recombinants carrying different parts of the T4 tail fiber gene cluster were identified by a marker rescue screen of 300 lambda T4 recombinant clones, generated by restriction of partial cytosine-containing T4 DNA with E coRI or with HindIII and ligation into appropriately cleaved lambda replacement vectors. Extensive genetic characterization revealed 15 recombinant classes with respect to the contiguous stretches of genome recovered and suggested the presence of 7 HindIII sites and 8 EcoRI sites in the 10 kb region. Functional analysis showed tht genes 34-38 were recovered intact. The tail fiber genes are efficiently expressed from lambda promoters and complement T4 amber mutants in a modified in vivo complementation test. Polypeptides, Mr = 145,000, 105,000, 39,000, 27,000 and 24,000 corresponding to gp34, gp37, gp35, gp38 and gp36 respectively, were detected by SDS polyacrylamide gel electrophoresis of 35S- labeled extracts of lambda T4 recombinant infected UV-treated host cells. Restriction enzyme structural analysis of the lambda T4 DNAs identified 7 HindIII and 7 EcoRI fragments and established a restriction map covering about 11 kb. The correlation of the genetic, functional and restriction maps provides a rational approach to a genetically directed DNA sequence analysis of the T4 tail fiber genes and of their mutant variants which affect particular aspects of tail fiber assembly, structure and function.