Emerging mechanisms of viral gene regulation from battles between host and SARS-CoV-2

点击翻译按钮获取中文摘要

PROJECT SUMMARY/ABSTRACT Over the last two decades, three highly pathogenic human coronaviruses, including SARS-CoV-2, have emerged, arguing that future deadly pandemics of new or re-emerging coronaviruses and other RNA viruses are almost inevitable. The urgent need to treat these fatal infectious diseases has prioritized the discovery and development of novel effective antivirals. However, despite the unprecedented efforts to address the COVID-19 crisis, highly effective COVID-19 therapeutics are severely limited due to the lack of a mechanistic understanding of coronavirus replication and pathogenesis. Most of the current research and therapeutic development efforts focus on SARS-CoV-2 RNA polymerase (RdRp) or spike protein, but their success can be severely undermined by a unique SARS-CoV-2 proofreading mechanism that excises incorporated RdRp inhibitors or by the rapid emergence of drug-resistant spike protein mutants. Therefore, it is imperative to develop innovative antiviral strategies targeting distinct, and in some cases yet to be identified, essential components of the viral life cycle. The intricate virus-host interplay constitutes a sophisticated regulatory network that dictates the outcome of virus infection, affording promising opportunities to be explored for innovative antiviral therapeutics. However, current knowledge of coronavirus-host interactions is mostly limited to the virus-host arms race in activating or blocking the interferon-dependent signaling pathways or in competing for host translation machinery. By contrast, virus- host interplay in coronavirus gene expression and regulation is largely uncharted territory. This major gap greatly hinders the design of novel antiviral agents targeting these much-overlooked coronavirus-host interactions that are critical for viral survival and host antiviral responses. The central objectives of this proposal are to define novel molecular mechanisms and functional roles of multiple recently discovered SARS-CoV-2-host interactions in modulating the viral replication and transcription processes and to identify new SARS-CoV-2-host interactions linked to novel mechanisms of viral gene regulation. With a combination of structural biology, protein-RNA biochemistry, single-molecule biophysics, cell virology, and computational approaches, we will accomplish these tasks through three tightly interwoven aims. In Aim 1, we will determine the molecular and structural basis of these newfound interactions between host factors and the viral replication-transcription machinery. In Aim 2, we will delineate the biological functions of these crucial host factors in modulating viral replication and transcription. In Aim 3, we will develop an innovative capture-identification-visualization experimental pipeline to discover new host factors and novel viral replication-transcription-regulating mechanisms. Together, these studies will establish an innovative conceptual framework to study coronavirus-host interactions and reveal new targets for the development of novel anti-coronavirus therapeutics.