title: Interaction of infectious spleen and kidney necrosis virus ORF119L with PINCH leads to dominant-negative inhibition of integrin-linked kinase and cardiovascular defects in zebrafish.
abstract: Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the Megalocytivirus genus, Iridoviridae family, causing a severe systemic disease with high mortality in mandarin fish (Siniperca chuatsi) in China and Southeast Asia. At present, the pathogenesis of ISKNV infection is still not fully understood. Based on a genome-wide bioinformatics analysis of ISKNV-encoded proteins, we found that ISKNV open reading frame 119L (ORF119L) is predicted to encode a three-ankyrin-repeat (3ANK)-domain-containing protein, which shows high similarity to the dominant negative form of integrin-linked kinase (ILK); i.e., viral ORF119L lacks the ILK kinase domain. Thus, we speculated that viral ORF119L might affect the host ILK complex. Here, we demonstrated that viral ORF119L directly interacts with particularly interesting Cys-His-rich protein (PINCH) and affects the host ILK-PINCH interaction in vitro in fathead minnow (FHM) cells. In vivo ORF119L overexpression in zebrafish (Danio rerio) embryos resulted in myocardial dysfunctions with disintegration of the sarcomeric Z disk. Importantly, ORF119L overexpression in zebrafish highly resembles the phenotype of endogenous ILK inhibition, either by overexpressing a dominant negative form of ILK or by injecting an ILK antisense morpholino oligonucleotide. Intriguingly, ISKNV-infected mandarin fish develop disorganized sarcomeric Z disks in cardiomyocytes. Furthermore, phosphorylation of AKT, a downstream effector of ILK, was remarkably decreased in ORF119L-overexpressing zebrafish embryos. With these results, we show that ISKNV ORF119L acts as a domain-negative inhibitor of the host ILK, providing a novel mechanism for the megalocytivirus pathogenesis.
  
  
  OBJECTIVE
  Our work is the first to show the role of a dominant negative inhibitor of the host ILK from ISKNV (an iridovirus). Mechanistically, the viral ORF119L directly binds to the host PINCH, attenuates the host PINCH-ILK interaction, and thus impairs ILK signaling. Intriguingly, ORF119L-overexpressing zebrafish embryos and ISKNV-infected mandarin fish develop similar disordered sarcomeric Z disks in cardiomyocytes. These findings provide a novel mechanism for megalocytivirus pathogenesis.
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Ji-Min
authors.initials: JM
authors.lastname: Yuan
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Bai-Liang
authors.initials: BL
authors.lastname: He
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Lu-Yun
authors.initials: LY
authors.lastname: Yang
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China School of Marine Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Guo
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China School of Marine Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Shao-Ping
authors.initials: SP
authors.lastname: Weng
authors.affiliation: CHOC Children's Hospital, University of California Irvine, Orange, California, USA.
authors.forename: Shengwen Calvin
authors.initials: SC
authors.lastname: Li
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China School of Marine Sciences, Sun Yat-sen University, Guangzhou, China lsshjg@mail.sysu.edu.cn.
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: He
mesh_terms: D000818:Animals; D002460:Cell Line; D003530:Cyprinidae; D004266:DNA Virus Infections / Q000473:pathology / Q000821:virology; D004195:Disease Models, Animal; D054884:Host-Pathogen Interactions; D007497:Iridoviridae / Q000502:physiology*; D009124:Muscle Proteins / Q000378:metabolism*; D009206:Myocardium / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D014764:Viral Proteins / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000099200:Scaffold Protein ILK
chemical_list: D009124:Muscle Proteins; D017346:Protein Serine-Threonine Kinases; D014764:Viral Proteins; D029961:Zebrafish Proteins; C562196:lims1 protein, zebrafish; C522180:ILK protein, zebrafish; D000099200:Scaffold Protein ILK