REGULATION OF MESSENGER RNA SYNTHESIS IN ESCHERICHIA COLI

Quantitative estimates of messenger activity have been obtained using RNA extracted from Escherichia coli to stimulate in vitro protein synthesis. The activity in extracts from cultures grown at different rates was nearly proportional to the amount of ribosomal RNA. In a mutant rich in 43 s ribosomal precursors and 30 s particles the same relationship was found. This suggests that the 30 s particle is active in releasing the messenger RNA from the template and might regulate messenger RNA synthesis. In stringent cells previously depleted of messenger by uracil starvation, messenger RNA synthesis was found to occur at identical rates in the presence or absence of a required amino acid upon re-addition of uracil. These results are compatible with a model in which the synthesis of messenger RNA is regulated by the 30 s particle independent of its participation in protein synthesis. © 1968.