Synthesis of ribosomal protein S1 following nutritional shift-up in Escherichia coli K-12.

The synthesis rate of ribosomal protein S1 was measured in Escherichia coli K-12 during the transitional period following a nutritional shift-up from acetate minimal to glucose/amino acids/nucleosides medium. The synthesis rate of S1 increased without a lag suggesting that the S1 gene is under stringent control and located very close to its promoter. The rate of S1 synthesis slowed between 7 and 15 min, and then increased to the postshift-up steady state rate. The postshift-up steady state rate was half the initial rate obtained between 0 and 7 min. The slow down in the synthesis rate between 7 and 15 min indicates that an unknown factor(s), in addition to guanosine 5'-diphosphate, 3'-diphosphate, participates in the regulation of S1 gene expression.