title: A novel C-type lectin from Eriocheir sinensis functions as a pattern recognition receptor with antibacterial activity.
abstract: As pattern recognition receptors (PRRs), C-type lectins (CTLs) play significant roles in recognizing and eliminating pathogens in innate immunity. In this study, a novel CTL (EsLecD) was identified from the crustacean Eriocheir sinensis. The cloning of full-length EsLecD cDNA was based on the initial expressed sequence tags (ESTs) isolated from a hepatopancreatic cDNA library. The full-length EsLecD cDNA of 686 bp with an open reading frame of 468 bp encodes a putative protein of 155 aa residues, including an N-terminal signal peptide and a single carbohydrate-recognition domain (CRD). By quantitative RT-PCR analysis, the EsLecD transcript was mainly detected in the hepatopancreas but rarely in other tissues, and it was significantly upregulated in the hepatopancreas after immune challenge with lipopolysaccharides. The recombinant EsLecD protein (rEsLecD) exhibited the ability to bind to all tested microorganisms, including bacteria and yeast. Meanwhile, calcium significantly increased the binding affinity of rEsLecD toward microorganisms, but it was not essential. The binding of rEsLecD induced the aggregation of microbial pathogens. Moreover, rEsLecD was capable of inhibiting the growth of microorganisms and even directly killing bacteria. Interestingly, rEsLecD could stimulate cellular encapsulation in vitro. In conclusion, results of this study suggest that EsLecD acts as an antibacterial PRR participating in the innate immunity of invertebrates.
authors.affiliation: School of Life Science, East China Normal University, Dong-Chuan Road No. 500, Shanghai 200241, China.
authors.forename: Xiao-Nv
authors.initials: XN
authors.lastname: Guo
authors.forename: Xing-Kun
authors.initials: XK
authors.lastname: Jin
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Ai-Qing
authors.initials: AQ
authors.lastname: Yu
authors.forename: Min-Hao
authors.initials: MH
authors.lastname: Wu
authors.forename: Shang-Jian
authors.initials: SJ
authors.lastname: Tan
authors.forename: You-Ting
authors.initials: YT
authors.lastname: Zhu
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Qun
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D003386:Brachyura / Q000276:immunology*; D002118:Calcium / Q000378:metabolism; D002681:China; D016000:Cluster Analysis; D019295:Computational Biology; D017931:DNA Primers / Q000235:genetics; D005786:Gene Expression Regulation / Q000276:immunology*; D015723:Gene Library; D043143:Hepatopancreas / Q000378:metabolism; D007113:Immunity, Innate / Q000276:immunology*; D037181:Lectins, C-Type / Q000276:immunology* / Q000378:metabolism; D008070:Lipopolysaccharides; D008969:Molecular Sequence Data; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D037181:Lectins, C-Type; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D002118:Calcium
keywords: Antibacterial activity; C-type lectin; Chinese mitten crab; Eriocheir sinensis; Innate immunity