title: Cflec-4, a multidomain C-type lectin involved in immune defense of Zhikong scallop Chlamys farreri.
abstract: C-type lectins are a superfamily of carbohydrate-recognition proteins which play crucial roles in the innate immunity. In this study, a novel multidomain C-type lectin gene from scallop Chlamys farreri (designated as Cflec-4) was cloned by RACE approach based on EST analysis. The full-length cDNA of Cflec-4 was of 2086 bp. The open reading frame was of 1830bp and encoded a polypeptide of 609 amino acids, including a signal sequence and four dissimilar carbohydrate-recognition domains (CRDs). The deduced amino acid sequence of Cflec-4 shared high similarities to other C-type lectin family members. The phylogenetic analysis revealed the divergence between the three N-terminal CRDs and the C-terminal one, suggesting that the four CRDs in Cflec-4 originated by repeated duplication of different primordial CRD. The potential tertiary structure of each CRD in Cflec-4 was typical double-loop structure with Ca2+-binding site 2 in the long loop region and two conserved disulfide bridges at the bases of the loops. The tissue distribution of Cflec-4 mRNA was examined by fluorescent quantitative real-time PCR. In the healthy scallops, the Cflec-4 transcripts could be only detected in gonad and hepatopancreas, whereas in the Listonella anguillarum challenged scallops, it could be also detected in hemocytes. These results collectively suggested that Cflec-4 was involved in the immune defense of scallop against pathogen infection and provided new insight into the evolution of C-type lectin superfamily.
authors.affiliation: The Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Lingling
authors.initials: L
authors.lastname: Wang
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Song
authors.forename: Jianmin
authors.initials: J
authors.lastname: Zhao
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.forename: Limei
authors.initials: L
authors.lastname: Qiu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D006090:Gram-Negative Bacteria / Q000276:immunology; D006434:Hemocytes / Q000276:immunology; D007113:Immunity, Innate; D037181:Lectins, C-Type / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000276:immunology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D049897:Pectinidae / Q000737:chemistry / Q000276:immunology* / Q000382:microbiology; D010802:Phylogeny; D017434:Protein Structure, Tertiary / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D037181:Lectins, C-Type