OASL triggered by a novel goose astrovirus via ORF2 restricts its replication.

Although astrovirus causes enteric diseases and encephalitis in humans, and nephritis and hepatitis in poultry, the infection of astrovirus is thought to be self-limiting. However, little is known about its molecular mechanism. In this study, we found a novel goose astrovirus GAstV-GD and its ORF2 could efficiently activate the innate immune response and induce a high level of OASL in vitro and in vivo The truncation assay for ORF2 further revealed that the P2 domain of ORF2 contributed to stimulate OASL, whereas the acidic C-terminus of ORF2 attenuated such activation. Moreover, the over-expression and knockdown of OASL could efficiently restrict and promote the viral replication of GAstV-GD, respectively. Our data not only given novel insights for elucidating the self-limiting infection of the astrovirus but also provided virus and host targets for fighting against astroviruses.IMPORTANCE Astroviruses cause gastroenteritis and encephalitis in human, and nephritis, hepatitis and gout disease in poultry. However, the host immune response activated by astrovirus is mostly unknown. Here, we found that a novel goose astrovirus GAstV-GD and its ORF2 protein could efficiently induce a high level of OASL in vitro and in vivo, which could feedback to restrict the replication of GAstV-GD, revealing novel innate molecules triggered by astroviruses, and highlighting the ORF2 of GAstV-GD and OASL can be as potential antiviral targets for astroviruses.