Agr system of Listeria monocytogenes EGD-e: role in adherence and differential expression pattern.
In this study, we investigated the agrBDCA operon in the pathogenic bacterium Listeria monocytogenes EGD-e. In-frame deletion of agrA and agrD resulted in an altered adherence and biofilm formation on abiotic surfaces, suggesting the involvement of the agr system of L. monocytogenes during the early stages of biofilm formation. Real-time PCR experiments indicated that the transcript levels of agrBDCA depended on the stage of biofilm development, since the levels were lower after the initial attachment period than during biofilm growth, whereas transcription during planktonic growth was not growth phase dependent. The mRNA quantification data also suggested that the agr system was autoregulated and pointed to a differential expression of the agr genes during sessile and planktonic growth. Although the reverse transcription-PCR experiments revealed that the four genes were transcribed as a single messenger, chemical half-life and 5' RACE (rapid amplification of cDNA ends) experiments indicated that the full size transcript underwent cleavage followed by degradation of the agrC and agrA transcripts, which suggests a complex regulation of agr transcription.
UMR 1229 Microbiologie du Sol et de l'Environnement, Université de Bourgogne, INRA, F-21000 Dijon, France.
Aurélie
A
Rieu
Stéphanie
S
Weidmann
Dominique
D
Garmyn
Pascal
P
Piveteau
Jean
J
Guzzo
D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial; D015964:Gene Expression Regulation, Bacterial; D008089:Listeria monocytogenes / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
C095698:Agr protein, Staphylococcus aureus; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012333:RNA, Messenger; D015534:Trans-Activators