DNA-dependent in vitro synthesis of bacteriophage enzymes.

Abstract

The mechanism by which the bacteriophage T4 regulates the sequential synthesis of virus-specific proteins has not been elucidated as yet. The phasing of protein synthesis in T4-infected Escherichia coli may be controlled by either transcriptional or translational constraints. In order to study these regulatory mechanisms we have developed an in vitro system which, in response to bacteriophage DNA, synthesizes both early and late enzymes. Since both transcription and translation are required for enzyme synthesis in this system, it affords an unusual opportunity for the study of bacteriophage development. The in vitro system, which is prepared from uninfected E. coli, has been fractionated into ribosomes and supernatant proteins. The ribosomes are the source of initiation factors, and the supernatant proteins contain the amino acid activating enzymes, elongation factors, and RNA polymerase. The system is relatively free of host transfer RNA (tRNA) and DNA; enzyme synthesis depends on added tRNA, and RNA...