Escherichia coli leucine-responsive regulatory protein (Lrp) controls lysyl-tRNA synthetase expression.
Using random Tn10 insertion mutagenesis, we isolated an Escherichia coli mutant strain affected in the regulation of lysU, the gene encoding the inducible form of lysyl-tRNA synthetase. The transposon giving rise to the altered expression of lysU was found inserted within lrp. The latter gene codes for the leucine-responsive regulatory protein (Lrp) which mediates a global response of the bacterium to leucine. An involvement of Lrp in the regulation of lysU was searched for by using a lysU-lacZ operon fusion. The following conclusions were reached: (i) inactivation of lrp causes an increased activity of the lysU promoter, whatever the growth conditions assayed, (ii) insertion of a wild-type lrp gene into a multi-copy plasmid significantly reduces lysU expression, and (iii) sensitivity of the lysU promoter to the presence of leucine in the growth medium is abolished in the lrp context.
Gazeau
M
M
Laboratoire de Biochimie, Unité de Recherche Associée 240 du Centre National de la Recherche Scientifique, Ecole Polytechnique, Palaiseau, France.
Delort
F
F
Dessen
P
P
Blanquet
S
S
Plateau
P
P
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015971:Gene Expression Regulation, Enzymologic; D007930:Leucine / Q000737:chemistry / Q000235:genetics*; D051756:Leucine-Responsive Regulatory Protein; D008250:Lysine-tRNA Ligase / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D014157:Transcription Factors
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C497278:Lrp protein, E coli; D014157:Transcription Factors; D051756:Leucine-Responsive Regulatory Protein; D008250:Lysine-tRNA Ligase; D007930:Leucine