The ORF3a protein of SARS-CoV-2 induces apoptosis in cells
Yujie Ren, Ting Shu, Di Wu, Jingfang Mu, Chong Wang, Muhan Huang, Yang Han, Xue-Yi Zhang, Wei Zhou, Yang Qiu, Xi Zhou
Abstract
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused the ongoing pandemic of Coronavirus Disease 2019. SARS-CoV-2 belongs to the genus Betacoronavirus of the Coronaviridae family, which includes SARS-CoV and Middle East respiratory syndrome coronavirus. 1 , 2 Coronavirus-encoded accessory proteins play critical roles in virus–host interactions and the modulation of host immune responses, thereby contributing to coronaviral pathogenicity via different strategies. 3 However, the functions of SARS-CoV-2-encoded accessory proteins are not well understood. Apoptosis is a predominant type of programmed cell death, and has been recognized as an important host antiviral defense mechanism that controls viral infection and regulates the inflammatory response. 4 , 5 Previous studies have reported that the SARS-CoV-encoded accessory protein ORF3a can induce apoptosis in cells, 6 , 7 leading to the question of whether SARS-CoV-2 ORF3a also has pro-apoptotic activity. Here, we investigated the potential apoptosis-inducing activity of SARS-CoV-2 ORF3a in different cell lines and compared the pro-apoptotic activities of SARS-CoV-2 ORF3a with those of SARS-CoV ORF3a using the same system.