relA overcomes the slow growth of cca mutants

The slow growth of stringent cca mutants can be overcome by mutation at the rel A locus. The elevated basal ppGpp to GTP ratio associated with the slow growth is also reversed by a rel A mutation. Mutation at a second locus (or loci), distinct from rel A or cca , which decreases the amount of defective tRNA, also increases the growth rate of stringent cca cells. The possibility of deleterious effects of tRNA-C-C in stringent cells is discussed.