King, J., Fitten, R., Mykolajewycz, N. and Floor, E. (1973) In: Virus Research (C.F. Fox and W.S. Robinson, eds.) Acdemic Press, NY, pp 259-277

Genetic control of T4 tail assembly

Of the twenty-one genes known to be required for T4 tail assembly, seventeen specify products needed for baseplate assembly and maturation, while four genes control formation and termination of the tail tube and contractile sheath. Many of the proteins specified by these genes have been identified by SDS gel electrophoresis, and analysis of structures accumulating in mutant infected cells has revealed the morphological roles of the major structural proteins. Genes specifying the major baseplate structural proteins map in one large cluster; genes specifying minor and catalytic proteins - probably involved in formation of the baseplate triggering machinery - map in a separate large cluster.

Many of the steps in tail assembly proceed in vitro in mixtures of extracts of mutant infected cells. The experiments suggest considerable regulation of morphogenesis atthe level of assembly; the free subunits do not interact; each protein reacts only with an organized substrate structure.

In collaboration with R.A. Crowther (Lab of Mol. Biol. Cambridge, England) we have obatained computer filtered electron micrographs of complete baseplates and baseplates lacking genetically defined protein species. The results suggest that it will be possible to analyze the function of the baseplate in terms of its moving gene products.

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