Synthesis and turnover of ribosomal ribonucleic acid in guanine-starved cells of Escherichia coli.

The relationship between the rate of RNA accumulation and the level of guanosine triphosphate was examined. Cells auxotrophic for guanine show a 6-fold drop in the intracellular level of GTP in response to the exhaustion of the exogenous guanosine supply. Contraction of the GTP pool results in a 2.5-fold reduction in the rate of RNA synthesis and the cessation of RNA accumulation. The decrease in the rate of RNA synthesis is seen to occur at the level of chain elongation. Analysis of RNA made in guanine-starved cells by competition-hybridization and sucrose gradient sedimentation suggests that the turnover of newly synthesized ribosomal RNA accounts for the observed failure of RNA to accumulate.