Control of β-Glucosyltransferase and Lysozyme Synthesis during T4 Deoxyribonucleic Acid-dependent Ribonucleic Acid and Protein Synthesis in Vitro

T4 DNA was used to stimulate RNA and protein synthesis in a cell-free extract prepared from uninfected Escherichia coli. Previously, this system was shown to synthesize active β-glucosyl transferase, an early T4 enzyme, and lysozyme, an enzyme which appears late during T4 infection. The detailed kinetics of specific enzyme synthesis in vitro has been studied further. Under conditions which were optimal for early enzyme synthesis, the appearance of β-glucosyl transferase preceded lysozyme synthesis by 4 to 5 min. The kinetics of partial reactions leading to enzyme synthesis in vitro was also investigated. Lysozyme-specific messenger RNA was synthesized after β-glucosyl transferase-specific messenger RNA, although transcription of the two genes was initiated simultaneously. The long delay in DNA-dependent lysozyme synthesis was overcome by elevated magnesium ion concentrations. This kinetics indicated that a barrier against lysozyme synthesis in vitro operated between initiation of RNA synthesis and RNA elongation. This phenomenon may relate to either delayed polar transcription of regions of T4 DNA distal to RNA polymerase binding sites or to the preferential elongation of some messages by E. coli RNA polymerase after binding to T4 DNA has occurred.