Post-transcriptional regulation of T4 enzyme synthesis

Abstract

The in vivo accumulation of functional messenger RNA (mRNA) specific for the bacteriophage T4-induced enzymes, lysozyme and deoxynucleotide kinase, has been studied. For each enzyme, two distinct cycles of mRNA accumulation and degradation can be observed during the first 40 min of infection at 37 °C. Lysozyme mRNA activity peaks at 15 min after infection and again at 29 min, whereas peaks of deoxynucleotide kinase mRNA are observed at 8 min and 32 min after infection. These cyclic patterns are not reflected in the kinetics of synthesis of the enzymes in vivo. Deoxynucleotide kinase mRNA extracted at 8 min or at 30 min after infection sediments in linear sucrose gradients over a broad range with a major component at 15S and minor component at 18S. Lysozyme mRNA extracted at 15 min or at 30 min after infection similarly sediments as two bands with sedimentation coefficients of 15S and 18S. These results indicate that the regulation of these two enzymes in T4-infected E. coli is mediated via post-transcriptional control mechanisms.