title: Grouper (Epinephelus coioides) BCR signaling pathway was involved in response against Cryptocaryon irritans infection.
abstract: B cell antigen receptor (BCR) plays a crucial role in B cell development and antibody production. It comprises membrane immunoglobulin non-covalently associated with CD79a/CD79b heterodimer. After B cell activation, initial extracellular signals are transduced by BCR complex and amplified by two protein tyrosine kinases, LYN and SYK, which then trigger various pathways. In the present study, we cloned grouper genes for BCR accessory molecules, EcCD79a (669 bp) and EcCD79b (639 bp), as well as two protein tyrosine kinases, EcLYN (1482 bp) and EcSYK (1854 bp). Homology analysis showed that all four molecules had a relatively high amino acid identity compared with those in other animals. Among them, they all shared the highest identity with Takifugu rubripes (EcCD79a 49%, EcCD79b 52%, EcLYN 82% and EcSYK 77%). The conserved features and important functional residues were analyzed. Together with IgM and IgT, tissue distribution analysis showed that all six molecules were mainly expressed in immune organs, particularly systematic immune organs. In groupers infected with Cryptocaryon irritans, up-regulation of EcCD79a and b, EcIgM and EcIgT were not seen in the early stage skin and gill until 14-21 days. Up-regulation of EcCD79a was seen in head kidney at most time points, while EcCD79a and b were only significantly up-regulated in day 14 spleen. Significant up-regulation of EcIgT were seen in day 21 head kidney and day 1, day14 spleen. Significant up-regulation of EcIgM were seen in day 1 head kidney and 12 h spleen. In addition, two protein kinase genes, EcLYN and EcSYK, were up-regulated in the skin at most time points, which suggested that B cells may be activated at the skin local infection site.
authors: College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors: Ze-Quan
authors: ZQ
authors: Mo
authors: College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors: Man
authors: M
authors: Yang
authors: College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors: Hai-Qing
authors: HQ
authors: Wang
authors: School of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510006, PR China.
authors: Yang
authors: Y
authors: Xu
authors: College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors: Mian-Zhi
authors: MZ
authors: Huang
authors: College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors: Guo-Feng
authors: GF
authors: Lao
authors: College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China; Guangdong Provincial Key Laboratory of Import and Export Technical Measures of Animal, Plant and Food, Technical Center of Guangdong Entry-Exit Inspection and Quarantine Bureau, Guangzhou 510623, Guangdong Province, PR China.
authors: Yan-Wei
authors: YW
authors: Li
authors: State Key Laboratory of Biocontrol/Key Laboratory of Aquatic Product Safety (Sun Yat-Sen University), Ministry of Education, The School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
authors: An-Xing
authors: AX
authors: Li
authors: School of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510006, PR China. Electronic address: xcluo@scut.edu.cn.
authors: Xiao-Chun
authors: XC
authors: Luo
authors: College of Marine Sciences, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China. Electronic address: dxm72@scau.edu.cn.
authors: Xue-Ming
authors: XM
authors: Dan
mesh_terms: D000818:Animals; D001492:Bass; D016798:Ciliophora / Q000502:physiology*; D016770:Ciliophora Infections / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology* / Q000469:parasitology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007113:Immunity, Innate; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020539:Sequence Analysis, Protein / Q000662:veterinary; D015398:Signal Transduction
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger
keywords: CD79; Cryptocaryon irritans; Epinephelus coioides; LYN; SYK