Overexpression of PrfA leads to growth inhibition of Listeria monocytogenes in glucose-containing culture media by interfering with glucose uptake.
Listeria monocytogenes strains expressing high levels of the virulence regulator PrfA (mutant PrfA* or wild-type PrfA) show strong growth inhibition in minimal media when they are supplemented with glucose but not when they are supplemented with glucose-6-phosphate compared to the growth of isogenic strains expressing low levels of PrfA. A significantly reduced rate of glucose uptake was observed in a PrfA*-overexpressing strain growing in LB supplemented with glucose. Comparative transcriptome analyses were performed with RNA isolated from a prfA mutant and an isogenic strain carrying multiple copies of prfA or prfA* on a plasmid. These analyses revealed that in addition to high transcriptional up-regulation of the known PrfA-regulated virulence genes (group I), there was less pronounced up-regulation of the expression of several phage and metabolic genes (group II) and there was strong down-regulation of several genes involved mainly in carbon and nitrogen metabolism in the PrfA*-overexpressing strain (group III). Among the latter genes are the nrgAB, gltAB, and glnRA operons (involved in nitrogen metabolism), the ilvB operon (involved in biosynthesis of the branched-chain amino acids), and genes for some ABC transporters. Most of the down-regulated genes have been shown previously to belong to a class of genes in Bacillus subtilis whose expression is negatively affected by impaired glucose uptake. Our results lead to the conclusion that excess PrfA (or PrfA*) interferes with a component(s) essential for phosphotransferase system-mediated glucose transport.
Marr
A K
AK
Theodor-Boveri-Institut (Biozentrum), Lehrstuhl für Mikrobiologie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Joseph
B
B
Mertins
S
S
Ecke
R
R
Müller-Altrock
S
S
Goebel
W
W
D001483:Base Sequence; D001692:Biological Transport; D017931:DNA Primers; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008089:Listeria monocytogenes / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D020411:Oligonucleotide Array Sequence Analysis; D010454:Peptide Termination Factors / Q000187:drug effects / Q000235:genetics*; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000037:antagonists & inhibitors / Q000378:metabolism; D012329:RNA, Bacterial; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D010454:Peptide Termination Factors; D012329:RNA, Bacterial; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D005947:Glucose