Disease relevance of leuV

• Sequence determinants for promoter strength in the leuV operon of Escherichia coli [1].

High impact information on leuV

• The expression of the hisG promoter is positively regulated by ppGpp, whereas that of the leuV promoter (of tRNA(1eu)) is negatively regulated by ppGpp [2].
• The leuV operon of Escherichia coli encodes three of the four genes for the tRNA1Leu isoacceptors [3].
• A mutation in the FIS binding site reduces transcription from a leuV promoter in strains containing FIS but has no effect on transcription in strains lacking FIS, indicating that FIS contributes to leuV expression in vivo [4].
• The leuV promoter open complexes were an order of magnitude more stable to heparin challenge than those of rrnBp(1) [5].
• When the cellular level of purine triphosphates was increased at slower growth rates by pyrimidine limitation, a 10% reduction in leuV promoter activity was seen [5].

Chemical compound and disease context of leuV

• In contrast, the expression of a leuV promoter (from Escherichia coli) template was relatively unaffected by the glutamate replacement [6].

Biological context of leuV

• The leuV operon also exhibited the stringent response in multicopy plasmids [7].
• The leuV promoter fused to the beta-galactosidase gene showed a decrease in efficiency in the presence of extrachromosomal copies of rRNA genes [7].
• Unlike rRNA operons which also display upstream activation, sequences responsible for this effect in the leuV promoter are separated into two regions, one between -76 and -47, and the other between -45 and -39 [1].
• Comparative analysis of regulation of the leuV promoter with and without upstream activating sequences (UAS) demonstrated that the binding site for factor of inversion stimulation (FIS) located in UAS is essential for maximal GRDC [5].
• We also find that RNA polymerase forms an unusual heparin-sensitive complex with the leuV promoter, having a downstream protection boundary of approximately -7, and that the first two nucleotides of the transcript, GTP and UTP, are required for formation of a heparin-stable complex that extends downstream of the transcription start site [4].

Associations of leuV with chemical compounds

• In nuclease protection assays, the leuV operon displayed the stringent response in response to leucine starvation, analog inhibition, and growth of a temperature-sensitive leucyl-tRNA synthetase mutant at nonpermissive temperatures [7].
• DNA fragments carrying the leuV promoter migrate aberrantly on polyacrylamide gels, a phenomenon usually associated with DNA bending [1].
• Structural variants of the leuV promoter which differentially affect these regulatory responses have been identified, suggesting that promoter targets for GRDC and SC may be different and that GRDC of the leuV promoter occurs in the absence of guanosine 3', 5'-bisdiphosphate [5].
• Glutamate replacement did not alter the ppGpp-mediated positive and negative regulation of the his and leuV promoter, respectively, in the in vitro system [6].

References