title: A C-type lectin that inhibits bacterial infection and facilitates viral invasion in black rockfish, Sebastes schlegelii.
abstract: C-type lectins (CTLs) are important pattern recognition receptors (PRRs) that play vital roles in innate immunity. In teleosts, a number of CTLs have been reported, but their in vivo effects on host defense are still limited. In this study, a CTL homolog (SsLec1) was identified from black rockfish, Sebastes schlegelii, and its structure, expression and biological function was analyzed. The open reading frame of SsLec1 is 633 bp, with a 5'- untranslated region (UTR) of 36 bp and a 3'- UTR of 117 bp. The deduced amino acid sequence of SsLec1 shares the highest overall identity (73.20%) with the CTL of Oplegnathus fasciatus. SsLec1 possesses conserved CTL features, including a carbohydrate-recognition domain, four disulfide bond-forming cysteine residues, the mannose-type carbohydrate-binding motif, the conserved calcium binding sites and a putative signal peptide. The expression of SsLec1 was highest in liver and could be induced by experimental infection with Listonella anguillarum. Recombinant SsLec1 (rSsLec1) purified from E. coli was able to bind and agglutinate the Gram-negative fish pathogens Vibrio ichthyoenteri and Vibrio vulnificus. The agglutinating ability of rSsLec1 was abolished in the presence of mannose or ethylenediaminetetraacetic acid. Further analysis showed that rSsLec1 could enhance phagocytosis by macrophages. In vivo experiments indicated that rSsLec1 could inhibit bacterial infection and promote viral invasion. Taken together, these results suggest that SsLec1 is a novel CTL that possesses apparent immunoregulation property and plays a critical role in host defense against pathogens invasion.
authors: Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
authors: Yong
authors: Y
authors: Liu
authors: Pearl River Fishery Research Institute, Chinese Academy of Fishery Sciences, China.
authors: Ning-Qiu
authors: NQ
authors: Li
authors: Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
authors: Xin-Peng
authors: XP
authors: Zhao
authors: Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
authors: Bin
authors: B
authors: Yue
authors: Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
authors: Shu-Wen
authors: SW
authors: He
authors: Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
authors: Zhi-Xin
authors: ZX
authors: Gao
authors: Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
authors: Shun
authors: S
authors: Zhou
authors: Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China. Electronic address: lissazhang06@163.com.
authors: Min
authors: M
authors: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005399:Fishes; D007113:Immunity, Innate; D037181:Lectins, C-Type / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D014733:Vibrio / Q000502:physiology*; D014735:Vibrio Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D037181:Lectins, C-Type; D012333:RNA, Messenger
keywords: Antibacterial; Bacterial agglutination; C-type lectin; Facilitate viral infection; Sebastes schlegelii