title: Identification of a C-type lectin from the bay scallop Argopecten irradians.
abstract: C-type lectins are Ca(2+) dependent carbohydrate-recognition proteins that play crucial roles in the invertebrate innate immunity, such as nonself recognition, activation of proPO system, antibacterial activity, promotion of phagocytosis and nodule formation. In this study, a novel C-type lectin of bay scallops Argopecten irradians (Ai Lec) was identified using expressed sequence tag (EST) and RACE techniques. The Ai Lec cDNA encoded a polypeptide of 171 amino acids with a putative signal peptide of 21 amino acid residues and a mature protein of 150 amino acids. The deduced amino acid sequence of Ai Lec was highly similar to those of the C-type lectins from other animals and contained a typical carbohydrate-recognition domain (CRD) of 131 residues, which has four conserved disulfide-bonded cysteine residues that define the CRD and two additional cysteine residues at the amino terminus. The expression of Ai Lec transcript was dominantly detected in the hepatopancreas and slightly detected in the haemocytes of normal scallops. 6 h after Vibrio anguillarum-challenge and 8 h after Micrococcus luteus-challenge, the temporal expression of Ai Lec mRNA in hemocytes was increased by 4.4- and 3.6-folds, respectively. The results suggested that Ai Lec was a constitutive and inducible acute-phase protein and might be involved in immune response to Gram-negative and Gram-positive microbial infection in bay scallop A. irradians.
authors.affiliation: Key Laboratory of Tropical Marine Environmental Dynamics (LED), South China Sea Institute of Oceanography, Chinese Academy of Sciences, Guangzhou, People's Republic of China. llingzhu@163.com
authors.forename: Ling
authors.initials: L
authors.lastname: Zhu
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Pei-Yuan
authors.initials: PY
authors.lastname: Qian
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006458:Hemolymph / Q000378:metabolism; D037181:Lectins, C-Type / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D049897:Pectinidae / Q000235:genetics*; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D037181:Lectins, C-Type; D012333:RNA, Messenger