title: Ferritin has an important immune function in the ark shell Scapharca broughtonii.
abstract: Ferritin, the principle cytosolic iron storage protein in the majority of living organisms, has important roles during immune process in invertebrates. Detailed information about ferritin in the ark shell Scapharca broughtonii, however, has been very limited. In this study, full-length ferritin (termed SbFer) was cloned by the rapid amplication of cDNA ends (RACE) method based upon the sequence from the transcriptome library. The cDNA contained a 182 bp 5'-untranslated region, a 519 bp open reading frame encoding a polypeptide of 172 amino acids, a 229 bp 3'-untranslated region, and three introns (902, 373 and 402 bp) embedded in four exons. There was an iron response element (IRE) in the 5'-untranslated region. The deduced amino acid sequence of SbFer possessed many characteristics of vertebrate H type ferritin, shared 63%-91% identity with mollusks and greater identity with vertebrate H type ferritin compared to the L type. The SbFer gene expression pattern examined by quantitative real-time PCR showed ferritin mRNA was expressed in all ark shell tissues examined. The highest levels of expression were found in hemocytes with decreasing levels of expression in foot, mantle, gill, adductor muscle and hepatopancreas. A challenge with Vibrio anguillarum resulted in time-dependent significant upregulation of SbFer mRNA, indicating SbFer participated actively in the bacterial defense process. Further analysis of the antibacterial activity indicated recombinant SbFer could function as an immune antibacterial agent to both Gram-positive and Gram-negative bacteria. Taken together, these results suggested strongly that ferritin of the ark shell is involved in immune defense against microbial infection and it is a constitutive and inducible acute-phase protein.
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, PR China.
authors.forename: Libing
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China. Electronic address: liuzh@ysfri.ac.cn.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China.
authors.forename: Biao
authors.initials: B
authors.lastname: Wu
authors.affiliation: College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, PR China.
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China.
authors.forename: Liqing
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China.
authors.forename: Jiteng
authors.initials: J
authors.lastname: Tian
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China.
authors.forename: Xiujun
authors.initials: X
authors.lastname: Sun
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China.
authors.forename: Aiguo
authors.initials: A
authors.lastname: Yang
mesh_terms: D000209:Acute-Phase Proteins / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005293:Ferritins / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism / Q000493:pharmacokinetics; D035925:Iron-Regulatory Proteins / Q000235:genetics; D049894:Scapharca / Q000235:genetics / Q000276:immunology*; D016415:Sequence Alignment; D014733:Vibrio / Q000276:immunology*
chemical_list: D000209:Acute-Phase Proteins; D018076:DNA, Complementary; D035925:Iron-Regulatory Proteins; D005293:Ferritins
keywords: Antibacterial activity; Ferritin; Immune response; Scapharca broughtonii