hnRNP C modulates MERS-CoV and SARS-CoV-2 replication by governing the expression of a subset of circRNAs and cognitive mRNAs

Host circular RNAs (circRNAs) play critical roles in the pathogenesis of viral infections. However, how viruses modulate the biogenesis of host proviral circRNAs to facilitate their replication remains unclear. We have recently shown that Middle East respiratory syndrome coronavirus (MERS-CoV) infection increases co-expression of circRNAs and their cognate messenger RNAs (mRNAs), possibly by hijacking specific host RNA binding proteins (RBPs). In this study, we systemically analysed the interactions between the representative circRNA–mRNA pairs upregulated upon MERS-CoV infection and host RBPs. Our analysis identified heterogeneous nuclear ribonucleoprotein C (hnRNP C) as a key host factor that governed the expression of numerous MERS-CoV-perturbed circRNAs, including hsa_circ_0002846, hsa_circ_0002061, and hsa_circ_0004445. RNA immunoprecipitation assay showed that hnRNP C could bind physically to these circRNAs. Specific knockdown of hnRNP C by small interfering RNA significantly (P