The Relationship of Protein Synthesis to Early Transcriptive Events in Bacteriophage T4-infected Escherichia coli B

Abstract

The relationship of early transcriptive events to protein synthesis has been studied in protoplasts of bacteriophage T4-infected Escherichia coli by division of the infection cycle into a period of transcription and one of translation with inhibitors of RNA and protein synthesis. The accumulation of specific messengers during an initial incubation in the presence of 5-methyltryptophan or chloramphenicol was determined by the inhibition of further RNA synthesis with rifamycin and the measurement of the increase in the activity of various early enzymes after the restoration of protein synthesis. Three groups of early enzymes could be distinguished operationally according to the manner in which the respective messenger RNA accumulated during incubation with 5-methyltryptophan. In the case of one early enzyme, deoxynucleotide kinase, the messenger RNA did not accumulate in the presence of 5-methyltryptophan, a suggestion that the transcription of this region of the phage DNA requires the prior synthesis of a specific phage-induced protein. It was also shown that early viral transcription is severely limited when the synthesis of phage-induced proteins is inhibited with chloramphenicol. These studies suggest that early transcriptive events in viral development may be regulated by the synthesis of specific proteins.