Transcriptional control of the isoleucine-valine messenger RNA's in E. coli K-12

Geoffrey J. Childs, Martin Freundlich

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Hybridization of messenger ribonucleic acid (mRNA) isolated from Escherichia Coli K-12 to deoxyribonucleic acid (DNA) from λCI857st68h80dilv was used to detect isoleucine-valine (ilv) specific mRNA. A number of strains partially constitutive for the isoleucine-valine enzymes had levels of ilv mRNA 2 to 3-fold higher than the parent strain. Starvation for any of the branched-chain amino acids resulted in a 20 to 23-fold increase in ilv mRNA as compared to repressed levels. These differences were not due to altered growth rates or to changes in the stability of ilv mRNA. These data indicate that regulation of the isoleucine-valine enzymes by multivalent repression occurs mainly at the level of transcription. Kinetics of elongation of ilv mRNA after repression are consistent with the assumption that the mechanism of multivalent repression involves the prevention of further initiations by RNA polymerase.

Original languageEnglish (US)
Pages (from-to)257-268
Number of pages12
JournalMGG Molecular & General Genetics
Issue number3
StatePublished - Sep 1975
Externally publishedYes

ASJC Scopus subject areas

  • Genetics


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