Atypical Divergence of SARS-CoV-2 Orf8 from Orf7a within the Coronavirus Lineage Suggests Potential Stealthy Viral Strategies in Immune Evasion
Russell Y. Neches, Nikos C. Kyrpides, Christos Ouzounis
Abstract
Orf8 is one of the most puzzling genes in the SARS lineage of coronaviruses, including SARS-CoV-2. Using sophisticated sequence comparisons, we confirm its origins from Orf7a, another gene in the lineage that appears as more conserved, compared to Orf8. Orf7a is a potential immune antagonist of known structure, while a deletion of Orf8 was shown to decrease the severity of the infection in a cohort study. The subtle sequence similarities imply that Orf8 has the same immunoglobulin-like fold as Orf7a, confirmed by structure determination. We characterize the subgroups of this superfamily and demonstrate the highly idiosyncratic divergence patterns during the evolution of the virus.
Topics & Concepts
Lineage (genetic)CoronavirusSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2)Evasion (ethics)Coronavirus disease 2019 (COVID-19)BiologyVirology2019-20 coronavirus outbreakSequence (biology)Immune systemGeneImmune escapeDivergence (linguistics)BetacoronavirusGeneticsMedicineOutbreakDiseaseInfectious disease (medical specialty)LinguisticsPhilosophyPathologySARS-CoV-2 and COVID-19 ResearchAnimal Virus Infections StudiesViral Infections and Immunology Research