[The role of ppGpp in the coordination of transcription of the ribosomal protein genes rplKAJL and RNA-polymerase rpoBC genes in Escherichia coli cells].

Transcription of the ribosomal protein genes rplKAJL and of the RNA polymerase genes proBC in the E. coli cells depends on the level of regulatory nucleotide ppGpp. The ppGpp acts as a negative regulator of transcription of the rpoBC genes in conditions of moderate deficiency of amino acids (after the cells were shifted down from amino acid rich to minimal media) or after incomplete deacylation of tRNA exerted by addition of serine-hydroxamate, or by partial inactivation of valyl-tRNA synthetase. Rifampicin of low concentrations, which inhibit total transcription not more than to 50%, stimulates transcription of the genes rpoBC and rplKAJL. It was estimated that stimulatory effect of rifampicin results from the ability of this antibiotic to decrease synthesis of ppGpp--the negative regulator of transcription of genes rplKAJL and rpoBC.