title: Regulation of expression of type I signal peptidases in Listeria monocytogenes.
abstract: The role of type I signal peptidases (SPases I) is to remove the signal peptides of preproteins exported by the general secretory pathway. The genome of Listeria monocytogenes contains a locus encoding three contiguous SPases I (denoted SipX, SipY and SipZ). The authors recently showed that SipX and SipZ perform distinct functions in protein secretion and bacterial pathogenicity. Here, the regulation of sip gene expression in broth and in infected eukaryotic cells was studied. The results show that expression of the three sip genes is (i) controlled by two distinct promoter regions that respond differently to growth phase and temperature variations, and (ii) influenced by PrfA (the transcriptional activator regulating most of the virulence genes of L. monocytogenes) and the stress proteins ClpC and ClpP. It was found that sip gene expression was strongly upregulated upon infection of eukaryotic cells when bacteria were still entrapped in the phagosomal compartment. This upregulation is compatible with the need of L. monocytogenes to optimize its production of virulence factors in the early stage of the intracellular cycle.
authors.affiliation: INSERM-U570, Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, 75730 Paris Cedex-15, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Raynaud
authors.affiliation: INSERM-U570, Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, 75730 Paris Cedex-15, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Charbit
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D018938:Caco-2 Cells / Q000382:microbiology; D003470:Culture Media; D049071:Endopeptidase Clp / Q000378:metabolism; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000254:growth & development / Q000472:pathogenicity*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010454:Peptide Termination Factors / Q000378:metabolism; D010588:Phagosomes / Q000382:microbiology; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; C087481:ClpC protein, Bacteria; D003470:Culture Media; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D010454:Peptide Termination Factors; D012697:Serine Endopeptidases; C026515:type I signal peptidase; D049071:Endopeptidase Clp