Rapid Diagnosis of Coronavirus by RNA-Directed RNA Transcription Using an Engineered RNA-based Platform.

A coronavirus disease (COVID-19) outbreak associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading widely through person-to-person transmission. Various detection approaches have been developed involving quantitative polymerase chain reaction (qPCR) methods, CRISPR-based systems, and direct targeting of specific coronavirus proteins. However, there have only been a few reports on the detection of RNA-dependent RNA polymerase (RdRP), the primer-independent RNA-replicable protein produced by the RNA genes of coronavirus. Here, we introduce a novel diagnostic methodology for COVID-19 using the RNA-directed and de novo RNA replicable function of RdRP. We devised an RNA platform for RdRP-induced transcription (RPRIT) that includes an RNA template that can be directly transcribed by RdRP. By utilizing RPRIT, the presence of RdRP can be readily confirmed within 30 min using isothermal incubation without PCR. This RdRP detection method can provide a new route for rapid diagnosis of RNA virus-infected patients.