An autophagy-related gene ATG14 promotes WSSV infection by facilitating autophagy in Cherax quadricarinatus

Abstract

The activation of autophagy was found to be positively correlated with white spot syndrome virus (WSSV) entry into host cells; however, the molecular regulation between autophagic initiation and WSSV entry is still poorly known. Herein, ATG14, a major member of autophagy initiation complex class III phosphatidylinositol-3-kinase (PI3KC3) complex 1 (PI3KC3-C1), playing a vital role in the formation of autophagy precursors, was studied on WSSV infection in a crustacean Cherax quadricarinatus. The CqATG14 gene was cloned with 1476 bp encoding 491 amino acids, which was widely expressed in all examined tissues of crayfish with the highest expression in hemocytes. Moreover, the gene expression of CqATG14 was significantly up-regulated at 6 and 12 hpi in crayfish hematopoietic tissue (Hpt) after WSSV infection. Importantly, the internalized WSSV virions was clearly decreased at an early infection stage of 2 hpi in CqATG14-silenced Hpt cells, causing the decrease of viral replication as the expression of both WSSV genes and viral protein VP28 were significantly down-regulated at a late infection stage after CqATG14 knocking down. Furthermore, the binding of CqATG14 to CqBeclin1 was determined by co-immunoprecipitation assay; meanwhile, the presence of CqGABARAP-II protein (a marker of autophagy activation) was significantly decreased in CqATG14-silenced Hpt cells. These data suggest that CqATG14 might promote the early infection of WSSV, probably resulting from the promotion of viral endocytosis via facilitating autophagy, which benefits the further exploration of molecular mechanism around WSSV-autophagy in crustaceans.