title: Identification and functional characterization of a novel antistasin/WAP-like serine protease inhibitor from the tropical sea cucumber, Stichopus monotuberculatus.
abstract: A novel antistasin/WAP-like serine protease inhibitor, named as StmAW-SPI, was identified from sea cucumber (Stichopus monotuberculatus) and functionally characterized in this study. The full-length cDNA of StmAW-SPI is 1917 bp in length with a 72 bp 5'-untranslated region (UTR), a 294 bp 3'-UTR and a 1551 bp open reading frame (ORF) encoding a protein of 516 amino acids with a deduced molecular weight of 54.56 kDa. The StmAW-SPI protein has 5-fold internal repeats (IRs) of antistasin domain and 6-fold IRs of WAP domain. For the gene structure, StmAW-SPI contains 10 exons separated by 9 introns. The StmAW-SPI mRNA expression pattern was determined using quantitative real-time PCR. The highest level of StmAW-SPI was found in the intestine, followed by coelomocytes, gonad, body wall and respiratory tree. The StmAW-SPI expressions were significantly up-regulated after polyriboinosinic polyribocytidylic acid [Poly (I:C)] or lipopolysaccharides (LPS) challenge in in vitro experiments performed in primary coelomocytes. In addition, the serine protease inhibitory activity and bacterial protease inhibitory activity of StmAW-SPI were examined, and the antibacterial activity was also demonstrated in this study. Our study, as a whole, suggested that StmAW-SPI might play a critical role in the innate immune defense of sea cucumber against microbial infections, by not only inactivating the serine protease but also inhibiting the growth of pathogens.
authors.affiliation: College of Medicine, Foshan University, Foshan, 528000, PR China. Electronic address: yanaifen@mail3.sysu.edu.cn.
authors.forename: Aifen
authors.initials: A
authors.lastname: Yan
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, PR China. Electronic address: rosemary166@sina.com.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Ren
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, PR China. Electronic address: chan1010@scsio.ac.cn.
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China. Electronic address: jiangxiao4367@126.com.
authors.forename: Xiao
authors.initials: X
authors.lastname: Jiang
authors.affiliation: College of Marine Science, South China Agricultural University, Guangzhou, 510642, PR China. Electronic address: hongyanlucky@scau.edu.cn.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Sun
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, PR China. Electronic address: hucq@scsio.ac.cn.
authors.forename: Chaoqun
authors.initials: C
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D007113:Immunity, Innate; D007447:Invertebrate Hormones / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D011070:Poly I-C / Q000494:pharmacology; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment / Q000662:veterinary; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D047528:Stichopus / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D018076:DNA, Complementary; D007447:Invertebrate Hormones; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D015842:Serine Proteinase Inhibitors; C053155:antistasin; D011070:Poly I-C
keywords: Antibacterial activity; Antistasin/WAP-like serine protease inhibitor; Innate immune; Stichopus monotuberculatus