Overexpression of nucleoprotein downregulates Rabies virus mRNA transcription

Abstract

Rabies is a fatal zoonotic disease of the central nervous system of mammals caused by Rabies lyssavirus (RABV), a member of the order Mononegavirales. Its single-stranded negative-sense RNA genome encodes five structural proteins: nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G), and large protein (L). N plays a pivotal role in nucleocapsid assembly, regulation of viral transcription and replication, and the formation of Negri bodies, cytoplasmic viral factories essential for viral replication. Consequently, overexpression of N may disrupt RABV replicative dynamics, offering insight into the mechanisms governing its replication cycle while identifying potential targets for antiviral intervention. This study evaluated the effects of transient expression of RABV N mRNA on viral replication using a plasmid-based expression system in BHK-21 cells. BHK-21 cells were transfected with the pcDNA3.1(+)/C-DYK plasmid containing the N gene from the Challenge Virus Standard (CVS-11) strain of RABV. Viral mRNA transcription and total genomic viral load were quantified using absolute RT-qPCR. Overexpression n N mRNA led to a downward trend in viral mRNA transcription levels, although total viral genomic load remained largely unaffected. These findings provide further insight into the regulatory function of N during RABV replication and suggest that modulating N expression influences viral transcriptional dynamics.