title: A new fibrinogen-related protein from Argopecten irradians (AiFREP-2) with broad recognition spectrum and bacteria agglutination activity.
abstract: Fibrinogen-related proteins (FREPs) are a kind of pattern recognition receptors (PRRs) containing fibrinogen-like (FBG) domains, and they play curial roles in the innate immune response. In the present study, a new FREP protein was identified from bay scallop Argopecten irradians (designated as AiFREP-2). The full-length cDNA of AiFREP-2 was of 1299 bp with an open reading frame of 762 bp encoding a polypeptide of 253 amino acids, including a signal sequence and an FBG domain. The FBG domain in AiFREP-2 was highly similar to those of ficolins, tenascins and other FREPs. The mRNA expression of AiFREP-2 could be detected in all the examined tissues with the highest level in gill. The mRNA expression of AiFREP-2 in hemocytes was significantly up-regulated post the stimulation of lipopolysaccharide (LPS), peptidoglycan (PGN) and β-glucan (GLU) (P < 0.01). The recombinant AiFREP-2 (rAiFREP-2) could bind not only different PAMP ligands including LPS, PGN and GLU, but also various microbes including Gram-negative bacteria (Vibrio anguillarum), Gram-positive bacteria (Staphylococcus aureus) and fungus (Pichia pastoris and Yarrowia lipolytica). Additionally, rAiFREP-2 exhibited obvious agglutination activity towards Gram-negative bacteria V. anguillarum and Gram positive bacteria S. aureus. The results indicated that AiFREP-2 was involved in the immune response against Gram-negative bacteria, Gram-positive bacteria and fungus as a PRR in bay scallop, and the information was helpful to understand the innate immune defense mechanisms of mollusks.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Chuanyan
authors.initials: C
authors.lastname: Yang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Wang
authors.affiliation: 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.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Huang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: lshsong@ms.qdio.ac.cn.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
mesh_terms: D000371:Agglutination; D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D001483:Base Sequence; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D049897:Pectinidae / Q000378:metabolism*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051192:Receptors, Pattern Recognition / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D012333:RNA, Messenger; D051192:Receptors, Pattern Recognition
keywords: Agglutination activity; Argopecten irradians; FREP; Innate immunity; Pattern recognition receptor