SARS-CoV-2 NSP12 utilizes various host splicing factors for replication and splicing regulation (preprint)

ABSTRACT

Background The RNA-dependent RNA polymerase (RdRp) is a crucial element in the replication and transcription of RNA viruses. Although the RdRps of lethal human coronaviruses SARS-CoV-2, SARS-CoV, and MARS-CoV have been extensively studied, the molecular mechanism of the catalytic subunit NSP12, which is involved in pathogenesis, remains unclear. Results In this study, the biochemical and cell biological results demonstrate the interactions between SARS-CoV-2 NSP12 and seven host proteins, including three splicing factors (SLU7, PPIL3, and AKAP8), suggesting that the polymerase activity and stability of SARS-CoV-2 RdRp were affected by them to varying degrees. Furthermore, the entry efficacy of SARS-CoV-2 pseudovirus considerably decreased when SLU7 or PPIL3 was knocked out, indicating that abnormal splicing of the host genome was responsible for this occurrence. In addition, NSP12 and its homologues from SARS-CoV and MARS-CoV suppressed thealternative splicing (AS) of cellular genes, which were influenced by the three splicing factors. Conclusions Overall, our research illustrates that SARS-CoV-2 NSP12 can engage with various splicing factors, thereby impacting virus entry, replication, and gene splicing. This not only improves our understanding of how viruses cause diseases but also lays the foundation for the development of antiviral therapies.