Regulation of RNA synthesis in Escherichia coli I. Characterization of cells subjected to simultaneous temperature and osmotic shock

Abstract

Cells of Escherichia coli can be made permeable to low molecular weight compounds while retaining a sizeable portion of whole cell capacities for overall RNA and protein synthesis when appropriately supplemented. Inducibility and cyclic 3′,5′-adenosine monophosphate dependence of β-galactosidase synthesis in these cells is similar to that shown by whole cells. Therefore these shocked cellular preparations have capacities for coupled RNA and protein synthesis substantially higher than either cell-free extracts or previously described permeable cell systems in which the acidsoluble pools are washed out by the permeabilization procedure. Shocked cell preparations from strains showing stringent control of RNA synthesis synthesize guanosine 5′-diphosphate 2′ or 3′-diphosphate in response to amino acid deprivation. This property together with the high capacity for RNA synthesis allows an investigation of nucleotide participation in the regulation of RNA synthesis in this permeable cell system.