Expression and functional characterization of a gene associated with retinoid-interferon-induced mortality 19 (GRIM-19) from orange-spotted grouper (Epinephelus coioides)

Abstract

GRIM-19 is a nuclear encoded subunit of complex I that has been implicated in apoptosis. The protein participates in multiple functions including the innate immune response. GRIM-19 has been studied in humans and other mammals; however, fish GRIM-19 has not been well characterized. In this study, a new GRIM-19 gene, EcGRIM-19, was isolated from the orange-spotted grouper (Epinephelus coioides) cDNA library, which was constructed following LPS treatment. EcGRIM-19 is a 582-bp gene that encodes a 144-amino acid protein. The gene is a true ortholog of mammalian GRIM-19. EcGRIM-19 exhibits ubiquitous and constitutive expression in the different tissues of the orange-spotted grouper. The expression levels of EcGRIM-19 are altered in the gill, spleen, kidney and liver after induction with LPS. The subcellular localization analysis demonstrated that the EcGRIM-19 protein is localized predominantly in the mitochondria. In addition, amino acids 30-50 of the protein are responsible for the mitochondrial localization of EcGRIM-19. The caspase assay demonstrated that the overexpression of GRIM-19 enhanced the cellular sensitivity to interferon(IFN)-beta- and retinoic acid (RA)-induced death in HeLa cells. The data presented in this study are important for further understanding the EcGRIM-19 gene function in fish. (c) 2012 Elsevier Ltd. All rights reserved.The fund from the Key Laboratory of Marine Bio-resources Sustainable Utilization (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences (LMB091006); the fund from the State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences (2010FB09); the fund from National Natural Science Foundation of China (41276163 and 30901117) and the Fundamental Research Funds from CAFS (2012A0403) supported this research