title: Association of a hepatopancreas-specific C-type lectin with the antibacterial response of Eriocheir sinensis.
abstract: Pattern recognition receptors (PPRs) are part of the initial step of a host defense against pathogens in detecting pathogen-associated molecular patterns. However, determinants of the specificity of this recognition by innate immune molecules of invertebrates remain largely unknown. In this study, we investigated the potential involvement of an invertebrate PRR C-type lectin in the antimicrobial response of the crustacean Eriocheir sinensis. Based on the initial expressed sequence tags (EST) of a hepatopancreatic cDNA library, the full-length EsLecF cDNA was cloned and determined to contain a 477-bp open reading frame encoding a putative 158-amino-acid protein. A comparison with other reported invertebrate and vertebrate C-type lectin superfamily sequences revealed the presence of a common carbohydrate recognition domain (CRD). EsLecF transcripts in E. sinensis were mainly detected in the hepatopancreas and were inducible by a lipopolysaccharide (LPS) injection. The recombinant EsLecF (rEsLecF) protein produced via a prokaryotic expression system and affinity chromatography was found to have a wide spectrum of binding activities towards various microorganisms, and its microbial-binding activity was calcium-independent. Moreover, the binding of rEsLecF induced the aggregation of microbial pathogens. Results of the microorganism growth inhibitory assay and antibacterial assay revealed capabilities of rEsLecF in suppressing microorganism growth and directly killing bacteria, respectively. Furthermore, rEsLecF could enhance cellular encapsulation in vitro. Collectively, the findings presented here demonstrated the successful isolation of a novel C-type lectin in a crustacean and highlighted its critical role in the innate immunity of an invertebrate.
authors.affiliation: School of Life Science, East China Normal University, Shanghai, China.
authors.forename: Xing-Kun
authors.initials: XK
authors.lastname: Jin
authors.forename: Xiao-Nv
authors.initials: XN
authors.lastname: Guo
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Min-Hao
authors.initials: MH
authors.lastname: Wu
authors.forename: You-Ting
authors.initials: YT
authors.lastname: Zhu
authors.forename: Ai-Qing
authors.initials: AQ
authors.lastname: Yu
authors.forename: Shang-Jian
authors.initials: SJ
authors.lastname: Tan
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: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000276:immunology / Q000494:pharmacology*; D060829:Arthropod Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D003386:Brachyura / Q000187:drug effects / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D002118:Calcium / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D020224:Expressed Sequence Tags; D015723:Gene Library; D043143:Hepatopancreas / Q000276:immunology* / Q000382:microbiology; D037181:Lectins, C-Type / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D060829:Arthropod Proteins; D037181:Lectins, C-Type; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D002118:Calcium