title: Ixodes ricinus tick lipocalins: identification, cloning, phylogenetic analysis and biochemical characterization.
abstract: BACKGROUND
  During their blood meal, ticks secrete a wide variety of proteins that interfere with their host's defense mechanisms. Among these proteins, lipocalins play a major role in the modulation of the inflammatory response.
  
  
  RESULTS
  Screening a cDNA library in association with RT-PCR and RACE methodologies allowed us to identify 14 new lipocalin genes in the salivary glands of the Ixodes ricinus hard tick. A computational in-depth structural analysis confirmed that LIRs belong to the lipocalin family. These proteins were called LIR for "Lipocalin from I. ricinus" and numbered from 1 to 14 (LIR1 to LIR14). According to their percentage identity/similarity, LIR proteins may be assigned to 6 distinct phylogenetic groups. The mature proteins have calculated pM and pI varying from 21.8 kDa to 37.2 kDa and from 4.45 to 9.57 respectively. In a western blot analysis, all recombinant LIRs appeared as a series of thin bands at 50-70 kDa, suggesting extensive glycosylation, which was experimentally confirmed by treatment with N-glycosidase F. In addition, the in vivo expression analysis of LIRs in I. ricinus, examined by RT-PCR, showed homogeneous expression profiles for certain phylogenetic groups and relatively heterogeneous profiles for other groups. Finally, we demonstrated that LIR6 codes for a protein that specifically binds leukotriene B4.
  
  
  CONCLUSIONS
  This work confirms that, regarding their biochemical properties, expression profile, and sequence signature, lipocalins in Ixodes hard tick genus, and more specifically in the Ixodes ricinus species, are segregated into distinct phylogenetic groups suggesting potential distinct function. This was particularly demonstrated by the ability of LIR6 to scavenge leukotriene B4. The other LIRs did not bind any of the ligands tested, such as 5-hydroxytryptamine, ADP, norepinephrine, platelet activating factor, prostaglandins D2 and E2, and finally leukotrienes B4 and C4.
authors.affiliation: Laboratory for Molecular Biology of Ectoparasites, IBMM, Université Libre de Bruxelles, Gosselies, Belgium.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Beaufays
authors.forename: Benoît
authors.initials: B
authors.lastname: Adam
authors.forename: Yves
authors.initials: Y
authors.lastname: Decrem
authors.forename: Pierre-Paul
authors.initials: PP
authors.lastname: Prévôt
authors.forename: Sébastien
authors.initials: S
authors.lastname: Santini
authors.forename: Robert
authors.initials: R
authors.lastname: Brasseur
authors.forename: Michel
authors.initials: M
authors.lastname: Brossard
authors.forename: Laurence
authors.initials: L
authors.lastname: Lins
authors.forename: Luc
authors.initials: L
authors.lastname: Vanhamme
authors.forename: Edmond
authors.initials: E
authors.lastname: Godfroid
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D017124:Conserved Sequence; D005260:Female; D020869:Gene Expression Profiling; D018884:Ixodes / Q000737:chemistry / Q000235:genetics*; D054834:Lipocalins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D013984:Tick Infestations / Q000469:parasitology; D013987:Ticks / Q000235:genetics
chemical_list: D054834:Lipocalins