title: Molecular cloning and characterization of canine fractalkine and its receptor CX3CR1.
abstract: Fractalkine, also known as CX(3)CL1, is a unique chemokine that mediates inflammatory responses and is involved in the pathogenesis of several inflammatory disorders, including inflammatory bowel disease (IBD) in humans. In this study, we isolated cDNAs encoding canine fractalkine and its receptor CX(3)CR1, and assessed the biological activity of these molecules. The deduced amino acid sequence of the canine fractalkine cDNA showed 66% and 57% identity to human and mouse homologs, respectively. The N-terminal chemokine domain of the canine fractalkine showed 68% and 65% identity to human and mouse counterparts, respectively. The canine CX(3)CR1 amino acid sequence showed close homology to its human (83% identity) and mouse (81% identity) counterparts. Fractalkine and CX(3)CR1 mRNA were detected in all tissues in this study. Relatively higher expression levels of fractalkine mRNA were observed in the brain, medulla spinalis, small intestine, and mesenteric lymph nodes (MLNs), whereas higher expression levels of CX(3)CR1 mRNA were observed in the medulla spinalis, brain, liver, small intestine, and MLNs. The cross-reactivities of anti-human fractalkine antibody and anti-rat CX(3)CR1 antibody to canine proteins were confirmed using recombinant canine fractalkine and a cell line overexpressing canine CX(3)CR1, respectively. A transwell chemotaxis assay showed that the recombinant canine fractalkine induced migration in canine lymphoid cells expressing CX(3)CR1. The present study will be useful in understanding the canine immune system and the immunopathogenesis of canine inflammatory diseases.
authors.affiliation: Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Tokyo 113-8657, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Maeda
authors.forename: Koichi
authors.initials: K
authors.lastname: Ohno
authors.forename: Ko
authors.initials: K
authors.lastname: Nakashima
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Fukushima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tsukamoto
authors.forename: Hiyoshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Aki
authors.initials: A
authors.lastname: Fujiwara
authors.forename: Yuko
authors.initials: Y
authors.lastname: Goto-Koshino
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Fujino
authors.forename: Hajime
authors.initials: H
authors.lastname: Tsujimoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001483:Base Sequence; D000073883:CX3C Chemokine Receptor 1; D054428:Chemokine CX3CL1 / Q000032:analysis / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D003001:Cloning, Molecular / Q000379:methods; D003429:Cross Reactions / Q000276:immunology; D004285:Dogs / Q000235:genetics; D005434:Flow Cytometry / Q000662:veterinary; D006801:Humans; D015151:Immunoblotting / Q000662:veterinary; D051379:Mice; D008969:Molecular Sequence Data; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D018121:Receptors, Cytokine / Q000032:analysis / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D015728:Receptors, HIV / Q000032:analysis / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D016415:Sequence Alignment / Q000662:veterinary; D012689:Sequence Homology, Nucleic Acid; D014018:Tissue Distribution
chemical_list: D000906:Antibodies; D000073883:CX3C Chemokine Receptor 1; D054428:Chemokine CX3CL1; D018121:Receptors, Cytokine; D015728:Receptors, HIV