title: Clr-a: A Novel Immune-Related C-Type Lectin-like Molecule Exclusively Expressed by Mouse Gut Epithelium.
abstract: The mouse gut epithelium represents a constitutively challenged environment keeping intestinal commensal microbiota at bay and defending against invading enteric pathogens. The complex immunoregulatory network of the epithelial barrier surveillance also involves NK gene complex (NKC)-encoded C-type lectin-like molecules such as NKG2D and Nkrp1 receptors. To our knowledge, in this study, we report the first characterization of the orphan C-type lectin-like molecule Clr-a encoded by the Clec2e gene in the mouse NKC. Screening of a panel of mouse tissues revealed that Clec2e transcripts are restricted to the gastrointestinal tract. Using Clr-a-specific mAb, we characterize Clr-a as a disulfide-linked homodimeric cell surface glycoprotein. Of note, a substantial fraction of Clr-a molecules are retained intracellularly, and analyses of Clr-a/Clr-f hybrids attribute intracellular retention to both the stalk region and parts of the cytoplasmic domain. Combining quantitative PCR analyses with immunofluorescence studies revealed exclusive expression of Clr-a by intestinal epithelial cells and crypt cells throughout the gut. Challenge with polyinosinic-polycytidylic acid results in a rapid and strong downregulation of intestinal Clr-a expression in contrast to the upregulation of Clr-f, a close relative of Clr-a, that also is specifically expressed by the intestinal epithelium and acts as a ligand of the inhibitory Nkrp1g receptor. Collectively, we characterize expression of the mouse NKC-encoded glycoprotein Clr-a as strictly associated with mouse intestinal epithelium. Downregulation upon polyinosinic-polycytidylic acid challenge and expression by crypt cells clearly distinguish Clr-a from the likewise intestinal epithelium-restricted Clr-f, pointing to a nonredundant function of these highly related C-type lectin-like molecules in the context of intestinal immunosurveillance.
authors.affiliation: Institute for Molecular Medicine, Johann Wolfgang Goethe University Frankfurt am Main, 60590 Frankfurt am Main, Germany.
authors.forename: Emilia
authors.initials: E
authors.lastname: Rutkowski
authors.affiliation: Institute for Molecular Medicine, Johann Wolfgang Goethe University Frankfurt am Main, 60590 Frankfurt am Main, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Leibelt
authors.affiliation: Institute for Molecular Medicine, Johann Wolfgang Goethe University Frankfurt am Main, 60590 Frankfurt am Main, Germany.
authors.forename: Christina
authors.identifier: 0000-0003-4439-4307
authors.initials: C
authors.lastname: Born
authors.affiliation: Institute for Molecular Medicine, Johann Wolfgang Goethe University Frankfurt am Main, 60590 Frankfurt am Main, Germany.
authors.forename: Miriam E
authors.initials: ME
authors.lastname: Friede
authors.affiliation: Institute for Immunology, Philipps University Marburg, 35043 Marburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Bauer
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Mainz Medical Center, 55131 Mainz, Germany; and.|Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, 60596 Frankfurt am Main, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Weil
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Mainz Medical Center, 55131 Mainz, Germany; and.|Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, 60596 Frankfurt am Main, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Koch
authors.affiliation: Institute for Molecular Medicine, Johann Wolfgang Goethe University Frankfurt am Main, 60590 Frankfurt am Main, Germany; alexander.steinle@kgu.de.
authors.forename: Alexander
authors.identifier: 0000-0001-5081-8503
authors.initials: A
authors.lastname: Steinle
mesh_terms: D000818:Animals; D002469:Cell Separation; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D007413:Intestinal Mucosa / Q000276:immunology*; D037181:Lectins, C-Type / Q000096:biosynthesis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D037181:Lectins, C-Type