title: Characterization and functional analysis of a novel C-type lectin from the swimming crab Portunus trituberculatus.
abstract: C-type lectins (CTLs) are a family of calcium-dependent carbohydrate-binding proteins. In the present study, a novel C-type lectin (designated as PtCTL1) was identified and characterized from Portunus trituberculatus. The full-length cDNA of PtCTL1 was of 702 bp, containing a 5' untranslated region (UTR) of 91 bp, a 3' UTR of 110 bp with a poly (A) tail, and an open reading frame (ORF) of 501 bp encoding a polypeptide of 166 amino acids with a putative signaling peptide of 21 amino acids. A C-type lectin carbohydrate-recognition domain (CRD) containing four conserved cysteines was identified in the amino acid sequence of PtCTL1. The cDNA fragment encoding the mature peptide of PtCTL1 was recombined into pET-21a(+) with a C-terminal hexa-histidine tag fused in-frame and expressed in Escherichia coli Origami (DE3). The recombinant PtCTL1 (rPtCTL1) can agglutinate all the tested bacteria, including three Gram-positive bacterial strains and three Gram-negative bacterial strains. In addition, erythrocyte agglutination and LPS-binding activity were observed in a Ca2+-dependent manner. The erythrocyte agglutination was inhibited by EDTA, indicating that PtCTL1 was Ca2+-dependent. The mRNA transcripts of PtCTL1 were detected mainly in the tissues of hepatopancreas and hemocytes and its levels were significantly up-regulated in hemocytes following Vibrio alginolyticus challenge. These results indicate that PtCTL1 may function as a pattern recognition receptor (PRR) for protecting P. trituberculatus from bacterial infection. Moreover, such findings also provide evidence for further understanding the innate immunology of invertebrate.
authors.affiliation: Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo 315211, China.
authors.forename: Junkai
authors.initials: J
authors.lastname: Lu
authors.affiliation: Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo 315211, China.
authors.forename: Zuoben
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo 315211, China. Electronic address: muchangkao@nbu.edu.cn.
authors.forename: Changkao
authors.initials: C
authors.lastname: Mu
authors.affiliation: Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo 315211, China.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Li
authors.affiliation: Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo 315211, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Song
authors.affiliation: Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo 315211, China.
authors.forename: Chunlin
authors.initials: C
authors.lastname: Wang
mesh_terms: D000371:Agglutination; D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003386:Brachyura / Q000187:drug effects / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D006386:Hemagglutination Tests; D037181:Lectins, C-Type / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014018:Tissue Distribution; D044149:Vibrio alginolyticus / Q000502:physiology*
chemical_list: D060829:Arthropod Proteins; D018076:DNA, Complementary; D037181:Lectins, C-Type; D008070:Lipopolysaccharides; D012333:RNA, Messenger
keywords: Agglutinating activity; C-type lectin; Innate immunity; Portunus trituberculatus