Influence of L-leucine and L-alanine on Lrp regulation of foo, coding for F1651, a Pap homologue.
The foo operon encodes F165 1 fimbriae that belong to the P-regulatory family and are synthesized by septicemic Escherichia coli. Using an Lrp-deficient host and the lrp gene cloned under the arabinose pBAD promoter, we demonstrated that foo was transcribed proportionally to the amount of Lrp synthesized. L-leucine and L-alanine decreased drastically the steady-state transcription of foo and modified phase variation, independently of the presence of FooI. Specific mutations in the C-terminal region of Lrp reduced or abolished the repressive effect of these amino acids, indicating that they modulate F165 1 by affecting Lrp.
Berthiaume
Frédéric
F
Département de Pathologie et Microbiologie, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
Crost
Cécile
C
Labrie
Vincent
V
Martin
Christine
C
Newman
Elaine B
EB
Harel
Josée
J
D000409:Alanine / Q000494:pharmacology*; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D007930:Leucine / Q000494:pharmacology*; D051756:Leucine-Responsive Regulatory Protein; D009154:Mutation; D009876:Operon; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D000942:Antigens, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C088773:F165 protein, E coli; C497278:Lrp protein, E coli; D014157:Transcription Factors; D051756:Leucine-Responsive Regulatory Protein; D036781:Fimbriae Proteins; D007930:Leucine; D000409:Alanine