title: A novel C-type lectin, Nattectin-like protein, with a wide range of bacterial agglutination activity in large yellow croaker Larimichthys crocea.
abstract: C-type lectins (CTLs) are generally recognized as a superfamily of Ca(2+)-dependent carbohydrate-binding proteins, which serve as pattern recognition receptors (PRRs) in innate immunity of vertebrates. In this study, the molecular characterization and immune roles of a novel CTL from Larimichthys crocea (designated as LcNTC) were investigated. LcNTC is a novel protein that shared 33%-49% homology with other teleosts CTLs. The full-length cDNA of LcNTC was composed of 859 bp with a 465 bp open reading frame encoding a putative protein of 154 residues. LcNTC contained a single CRD with four conserved disulfide-bonded cysteine residues (Cys(57)-Cys(148), Cys(126)-Cys(140)) and EPN/AND motifs instead of invariant EPN/WND motifs required for carbohydrate-binding specificity and constructing Ca(2+)-binding sites. LcNTC mRNA was detected in all examined tissues with the most abundant in the gill. After challenged with poly I:C and Vibrio parahaemolyticus, the temporal expression of LcNTC was significantly up-regulated in the liver, spleen and head-kidney. LcNTC transcripts were also induced in the gill, skin, spleen and head-kidney post-infection with Cryptocaryon irritans. The recombinant LcNTC (rLcNTC) purified from Escherichia coli BL21 (DE3) exhibited strong agglutination activity against erythrocytes from human, rabbit and large yellow croaker in a Ca(2+)-dependent manner, and the agglutination could be inhibited by D-Mannose, D-Glucose, D-Fructose, α-Lactose, D-Maltose and LPS. Positive microbial agglutination activities of rLcNTC were observed against all tested bacteria in the presence of Ca(2+), including Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus and Micrococcus lysoleikticus) and Gram-negative bacteria (E. coli, V. parahaemolyticus, Vibrio alginolyticus and Aeromonas hydrophila). These findings collectively indicated that LcNTC might be involved in the innate immunity of L. crocea as a PRR.
authors.affiliation: Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen, 361021, China.
authors.forename: Changhuan
authors.initials: C
authors.lastname: Lv
authors.affiliation: Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen, 361021, China.
authors.forename: Dongling
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen, 361021, China. Electronic address: zywang@jmu.edu.cn.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016798:Ciliophora / Q000502:physiology; D016770:Ciliophora Infections / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology / Q000469:parasitology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007113:Immunity, Innate; D037181:Lectins, C-Type / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010473:Perciformes / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011897:Random Allocation; D016415:Sequence Alignment / Q000662:veterinary; D014735:Vibrio Infections / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D014736:Vibrio parahaemolyticus / Q000502:physiology
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D037181:Lectins, C-Type; D012333:RNA, Messenger; D011070:Poly I-C
keywords: Bacterial agglutination; Carbohydrate-binding activity; Expression; Haemagglutination; Lectin