Molecular characterization and expression profiling of caveolin-1 from Amphiprion clarkii and elucidation of its involvement in antiviral response and redox homeostasis.

Abstract

Caveolin-1 (Cav-1), a major structural component of caveolae, is involved in various biological functions, such as endocytosis, cholesterol trafficking, transcytosis, signal transduction, and immunity. To date, three caveolin members have been identified in mammals: Cav-1, Cav-2, and Cav-3. In this study, we identified the Cav-1 sequence from Amphiprion clarkii (AcCav-1). The protein is 181 amino acids long, with a molecular weight of 20.73kDa and a predicted isoelectric point of 5.48. The phylogenetic tree disclosed that AcCav-1 is closely related to teleost fish orthologs and clusters together with vertebrates. It shares the highest identity (99.4%) and similarity (100%) with Amphiprion ocellaris. Subcellular localization assays showed that Cav-1 expressed in the endoplasmic reticulum and cytoplasm. Further, AcCav-1 was ubiquitously expressed in all examined tissues, but most highly in the skin and the spleen. The up and downregulation of AcCav-1 was observed throughout the testing period after in-vivo immunostimulation with lipopolysaccharides (LPS), polyinosinic:polycytidylic acid (poly (I:C), and Vibrio harveyi (V. harveyi). The antiviral assay showed that AcCav-1 overexpression suppresses the replication of the viral hemorrhagic septicemia virus (VHSV) in Fathead minnow cells by activating antiviral genes. Further, LPS induced NO production and H2O2-mediated oxidative stress assays showed that AcCav-1 is involved in the regulation of oxidative stress. Collectively, these findings suggest the indispensable role of Cav-1 in the immune system of A.clarkii.