THE SYNTHESIS OF MESSENGER RNA WITHOUT PROTEIN SYNTHESIS IN NORMAL AND PHAGE-INFECTED THYMINELESS STRAINS OF ESCHERICHIA COLI

Abstract

Escherichia coli deficient in the ability to synthesize thymine, uracil, and an amino acid synthesize a small fraction of their normal RNA from uracil in the absence of thymine and the amino acid. The synthesis of even this fraction of RNA is markedly inhibited by concomitant DNA synthesis. The RNA made appears on the ribosomes. When synthesized in the presence of an inducer of [beta]-galactosidase, the RNA made permits the rapid synthesis of a small amount of this enzyme in the apparent absence of the inducer. T6r+-infected cells make characteristic phage-induced RNA in the absence of protein synthesis. Such RNA stimulates a rapid synthesis of the early enzyme, dCMP hydroxymethylase, in the infected cells but not of the late enzyme, lysozyme. Evidence is presented to support the hypothesis that the sequential production of phage proteins may be determined by the sequential transcription of the phage genome, i.e., the sequential production of phage-induced messenger RNA.