title: Identification, expression pattern and potential role of variable lymphocyte receptor Aj-VLRA from Apostichopus japonicus in response to bacterial challenge.
abstract: The variable lymphocyte receptors (VLRs) are found in jawless vertebrates (agnathans), and specifically recognize bacteria and viruses via their leucine-rich repeats (LRRs). VLRs are believed to be adaptive immune response molecules. Echinoderms do not have adaptive immune systems; however, in the present study, a VLR cDNA named Aj-VLRA was cloned and characterized from sea cucumber, Apostichopus japonicus. The complete cDNA of Aj-VLRA was 3072 bp, including a 1995 bp open reading frame encoding 664 amino acids comprising LRR domains, a predicted transmembrane helix and an N-terminal signal peptide. As determined by quantitative real-time reverse transcription polymerase chain reaction, Aj-VLRA transcripts are ubiquitously expressed in the body wall, longitudinal muscles, intestine and respiratory tree of A. japonicus. The expression level of Aj-VLRA was upregulated after challenge with four common marine bacteria. In situ hybridization showed that the expression of Aj-VLRA was widely distributed in the four tissues, particularly in the cytoplasm of epidermal cells. Recombinantly expressed Aj-VLRA (including the LRR domains) could bind to bacteria including Micrococcus lysodeikticus (Gram+) and Vibrio anguillarum (Gram-). Collectively, the results suggested that Aj-VLRA is related to an innate immune response of A. japonicus.
authors.affiliation: College of Life Sciences, Liaoning Normal University, Dalian 116081, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: College of Life Sciences, Liaoning Normal University, Dalian 116081, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Yao
authors.affiliation: College of Life Sciences, Liaoning Normal University, Dalian 116081, China.
authors.forename: Huazhong
authors.initials: H
authors.lastname: Ba
authors.affiliation: College of Life Sciences, Liaoning Normal University, Dalian 116081, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Qin
authors.affiliation: College of Life Sciences, Liaoning Normal University, Dalian 116081, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Luan
authors.affiliation: College of Life Sciences, Liaoning Normal University, Dalian 116081, China.
authors.forename: Zhengmin
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Life Sciences, Liaoning Normal University, Dalian 116081, China. Electronic address: houlin@lnnu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Hou
authors.affiliation: Department of Biotechnology, Dalian Medical University, Dalian 116044, China. Electronic address: zouxiangyang@126.com.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Zou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D007113:Immunity, Innate; D008837:Micrococcus / Q000502:physiology; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D011971:Receptors, Immunologic / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D047528:Stichopus / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D014733:Vibrio / Q000502:physiology
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D011994:Recombinant Proteins
keywords: Apostichopus japonicus; Cloning; Innate immunity; Prokaryotic expression; Variable lymphocyte receptor; qRT-PCR