title: A novel alternative spliced chondrolectin isoform lacking the transmembrane domain is expressed during T cell maturation.
abstract: Chondrolectin (CHODL) is a novel type I transmembrane protein containing one carbohydrate recognition domain (CRD) of C-type lectins. Recently, data base searching revealed a variant of CHODL (AK022689) with a different 5' leader sequence derived from a new putative upstream alternative promoter (P2). The P2 promoter gives rise to at least three additional alternatively spliced isoforms, designated as CHODLf, CHODLf Delta E, and CHODL Delta E. Of all variants, the alternative exon E-splicing isoforms (CHODLf Delta E/CHODL Delta E) are expressed exclusively in the T lymphocyte lineage and are regulated during T lymphopoiesis. Peripheral T lymphocytes demonstrated a unique exon E-splicing pattern in comparison with end maturation stage thymocytes, suggesting its association with the post-thymic maturation of T cells. Since exon E encodes the transmembrane domain of CHODL, the exon E-skipping variant results in a non-transmembrane domain-containing isoform (CHODLf Delta E/CHODL Delta E) terminating in the QDEL sequence, thus suggesting different functional attributes of CHODL isoforms during the development of T cells. Double label immunofluoresence experiments demonstrated that the transmembrane-containing isoform (CHODLf) colocalizes with rBet1 to the endoplasmic reticulum-Golgi apparatus. In summary, this study describes the molecular characterization of novel members of the chondrolectin family associated with T cell maturation and a subcellular localization of CHODLf in the endoplasmic reticulum-Golgi apparatus.
authors.affiliation: Laboratory of Molecular Biotechnology, Department of Biomedical Sciences, University of Antwerp, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Lin
authors.initials: L
authors.lastname: Weng
authors.forename: Dirk R
authors.initials: DR
authors.lastname: Van Bockstaele
authors.forename: Jan
authors.initials: J
authors.lastname: Wauters
authors.forename: Eric
authors.initials: E
authors.lastname: Van Marck
authors.forename: Jean
authors.initials: J
authors.lastname: Plum
authors.forename: Zwi N
authors.initials: ZN
authors.lastname: Berneman
authors.forename: Jozef
authors.initials: J
authors.lastname: Merregaert
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001854:Bone Marrow Cells / Q000737:chemistry / Q000166:cytology; D019556:COS Cells; D002462:Cell Membrane / Q000737:chemistry*; D002469:Cell Separation; D004721:Endoplasmic Reticulum / Q000737:chemistry; D005091:Exons; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006056:Golgi Apparatus / Q000737:chemistry; D049452:Green Fluorescent Proteins; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000737:chemistry / Q000166:cytology; D006801:Humans; D037181:Lectins, C-Type / Q000032:analysis / Q000737:chemistry / Q000235:genetics*; D008164:Luminescent Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000032:analysis / Q000737:chemistry / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000502:physiology* / Q000648:ultrastructure; D014162:Transfection; D014407:Tumor Cells, Cultured; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D037181:Lectins, C-Type; D008164:Luminescent Proteins; D008565:Membrane Proteins; D020033:Protein Isoforms; D000097573:Red Fluorescent Protein; C475168:CHODL protein, human