Molecular Cloning and Characterization of Human Chondrolectin, a Novel Type I Transmembrane Protein Homologous to C-Type Lectins

Abstract

CHODL, a novel human gene encoding chondrolectin, was isolated by PCR screening. It is localized at chromosome 21q21 and consists of six exons and five introns. The open reading frame of CHODL encodes a type I transmembrane protein containing a single carbohydrate recognition domain (CRD) of C-type lectins in its extracellular portion. CHODL was detected as a 2.6-kb transcript by northern blot using enriched human testis RNA. RT-PCR analysis revealed preferential expression of CHODL in testis, prostate, and spleen. Immunohistochemistry demonstrated that the expression of CHODL is mainly limited to vascular muscle of testis, smooth muscle of prostate stroma, heart muscle, skeletal muscle, crypts of small intestine, and red pulp of spleen. Western blot analysis revealed that CHODL is an N-glycosylated protein with a molecular weight of approximately 36 kDa. In transiently transfected COS1 cells, CHODL shows a predominantly perinuclear localization. Although the predicted CHODL protein shares a significant homology (45% overall and 60% within the CRD) with layilin, a recently identified hyaluronan receptor, we failed to detect a specific interaction between CHODL and hyaluronan using cetylpyridinium chloride precipitation.