[Regulation of transcription by elements of the translation system in Escherichia coli].

The study of the structure of the operons tryptophan, phenylalanine and histidine has indicated that the transcription of these operons is controlled by the level of aminoacylation of the corresponding tRNAs which modulates the termination of transcription at an attenuator site. The derepression of the level of two enzymes responsible for the biosynthesis of glutamate and glutamine in Escherichia coli, following a decrease of the level of aminoacylation of tRNAglutamate in vivo, suggests that attenuator sites are involved in the control of the transcription of the two operons coding for these enzymes. The fact that tRNAglutamate is involved in this regulation whereas tRNAglutamine is not, supports the model of an evolution of the gene for the glutaminyl-tRNA synthetase of E. coli from the gene of a primitive glutamyl-tRNA synthetase similar to that of Bacillus subtilis.