title: Glycerophosphorylcholine regulates Haemophilus influenzae glpQ gene expression.
abstract: An important virulence strategy adopted by Haemophilus influenzae to establish a niche on the mucosal surface of the host is the phosphorylcholine (ChoP) decoration of its lipopolysaccharides, which promotes adherence to the host cells. Haemophilus influenzae is able to use glycerophosphorylcholine (GPC) from host for ChoP synthesis. Utilization of GPC requires glpQ, which encodes a glycerophosphodiester phosphodiesterase enzyme. In this study, we investigate the transcriptional regulation of glpQ gene using real-time PCR and transcriptional fusion of H. influenzae glpQ promoter to the Escherichia coli lacZ reporter gene. The glpQ promoter activities were examined under environmental conditions including changes in temperature, oxygen, high salt and minimal growth medium. Our data showed that under room temperature and anaerobic conditions, the glpQ gene expression levels were significantly higher than under other growth conditions. In addition, the glpQ gene expression levels were upregulated in the presence of GPC. These results suggest that H. influenzae may upregulate glpQ expression in response to different environments it encounters during infection, from the airway surfaces (room temperature) to deep tissues (anaerobic). Upregulation of glpQ by GPC may allow efficient use of abundant GPC from mammalian cells by H. influenzae as a source of nutrient and for ChoP decoration of lipopolysaccharide that facilitates bacterial adhesion to host cells and growth during infection.
authors.affiliation: Department of Biology, West Chester University of Pennsylvania, West Chester, PA 19383, USA.
authors.forename: Enas
authors.initials: E
authors.lastname: Alrousan
authors.affiliation: Department of Biology, West Chester University of Pennsylvania, West Chester, PA 19383, USA xfan@wcupa.edu.
authors.forename: Xin
authors.initials: X
authors.lastname: Fan
mesh_terms: D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D050939:Gene Fusion; D005997:Glycerylphosphorylcholine / Q000378:metabolism*; D006193:Haemophilus influenzae / Q000235:genetics* / Q000254:growth & development*; D007072:Immunoglobulin D / Q000235:genetics* / Q000378:metabolism; D007763:Lac Operon; D008074:Lipoproteins / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D007072:Immunoglobulin D; D008074:Lipoproteins; D005997:Glycerylphosphorylcholine; C067989:glpQ protein, Haemophilus influenzae
keywords: choline; colonization; pathogenesis; stress