Four C1q domain-containing proteins involved in the innate immune response in Hyriopsis cumingii.
C1q is a key subcomponent of the complement C1 complex. This subcomponent contains a globular C1q (gC1q) domain with remarkable ligand binding properties. C1q domain-containing (C1qDC) proteins are composed of all proteins with a gC1q domain. C1qDC proteins exist in many invertebrates and recognize non-self-ligands. In our study, four C1qDC genes, namely, HcC1qDC1-HcC1qDC4, were identified from Hyriopsis cumingii. HcC1qDC1-HcC1qDC4 encode a protein of 224, 204, 305, and 332 amino acids, respectively. All C1qDC proteins consist of a gC1q domain at the C terminal. In addition to the gC1q domain, a coiled-coil region is found in HcC1qDC4. Multiple alignments and phylogenetic tree analysis revealed that the C1qDC proteins highly differ from one another. Tissue distribution analysis demonstrated that HcC1qDC1-HcC1qDC4 are widely distributed in hemocytes, hepatopancreas, gills, mantle, and foot. These C1qDC genes are regulated by bacteria to varying degrees. These recombinant HcC1qDC proteins exhibit a binding activity against different bacterial species. Our results may suggest the roles of HcC1qDC genes in anti-bacterial immune defense.
College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, PR China; Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, PR China.
Ling-Ling
LL
Zhao
State Key Laboratory Breeding Base of Marine Genetic Resource, Third Institute of Oceanography, SOA, Xiamen, 361005, PR China.
Min
M
Jin
East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, PR China.
Xin-Cang
XC
Li
Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, PR China; Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences, Zhejiang University, Hangzhou, 310058, PR China. Electronic address: renqian0402@126.com.
Qian
Q
Ren
College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, PR China. Electronic address: lanjiangfeng@mail.hzau.edu.cn.
Jiang-Feng
JF
Lan
D016980:Aeromonas hydrophila / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015922:Complement C1q / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D043143:Hepatopancreas / Q000276:immunology / Q000382:microbiology; D007113:Immunity, Innate / Q000235:genetics*; D009928:Organ Specificity; D010802:Phylogeny; D016415:Sequence Alignment; D013211:Staphylococcus aureus / Q000502:physiology; D049876:Unionidae / Q000235:genetics* / Q000276:immunology / Q000382:microbiology
D015922:Complement C1q
Bacterial binding; C1qDC protein; Hyriopsis cumingii; Innate immunity