title: [Funtional study of gene relA in the expression of amino acid operons. III. The effect of the allelic state of gene relA on the derepression of the threonine and isoleucine-valine operons of Escherichia coli K-12].
abstract: During the derepression of threonine and isoleucine-valine operons the increase of activity of homoserine dehydrogenase and threonine deaminase respectively occurs only in relA+ strains of Escherichia coli K-12, while the activity of these enzymes in relA mutants does not change. The increase of the activity of homoserine dehydrogenase in relA+ strains corresponds to the increase of the fraction of the thr-mRNA, i.e. the expression of threonine operon is regulated at the level of transcription. After isoleucine is exhausted, only relA+ cells of threonine producer MG442 increase homoserine dehydrogenase activity and production of threonine. Thus, the regulation of transcription and translation of threonine and isoleucine-valine operons depends upon the allelic state of the relA gene.
mesh_terms: D000483:Alleles; D000596:Amino Acids / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005796:Genes; D006715:Homoserine Dehydrogenase / Q000235:genetics; D007532:Isoleucine / Q000235:genetics*; D009876:Operon; D014176:Protein Biosynthesis; D013912:Threonine / Q000235:genetics*; D013913:Threonine Dehydratase / Q000235:genetics; D014158:Transcription, Genetic; D014633:Valine / Q000235:genetics*
chemical_list: D000596:Amino Acids; D007532:Isoleucine; D013912:Threonine; D006715:Homoserine Dehydrogenase; D013913:Threonine Dehydratase; D014633:Valine
vernacular_title: Issledovanie funktsii gena relA v vyrazhenii aminokislotnykh operonov. Soobshchenie III. Vliianie allel'nogo sostoianiia gena relA na derepressiiu treoninovogo i izoleĭtsinvalinovogo operonov Escherichia coli K-12.