Viral replication complex (VRC)

The viral replication complex (VRC) is an essential multi-protein assembly composed of viral non-structural proteins and host-derived factors that facilitates the replication and transcription of the viral genome within an infected host cell [5, 7]. For many positive-strand RNA viruses, such as SARS-CoV-2 and hepatitis C virus (HCV), the VRC is localized within specialized membrane-bound organelles, such as double-membrane vesicles, to concentrate substrates and shield viral RNA from the host's innate immune sensors [11, 14]. This macromolecular complex serves as a critical therapeutic target because it houses key enzymatic activities, including RNA-dependent RNA polymerase (RdRp), helicases, and proteases required for viral propagation [3, 14]. Direct-acting antivirals (DAAs) like remdesivir and sofosbuvir target components of the VRC to inhibit nucleic acid synthesis through chain termination or lethal mutagenesis [3, 4, 6]. Clinically, monitoring the efficacy of VRC-targeting drugs involves measuring viral load and identifying resistance-associated mutations in the complex's enzymatic domains [11, 12]. Major therapeutic challenges include the high mutation rate of viruses leading to rapid drug resistance and the potential for off-target toxicity against essential host cellular or mitochondrial polymerases [1, 14, 15].

Other names

Viral replicaseReplication-transcription complex (RTC)RNA replicase machineryViral replication organelle (RO)-associated complexViral transcription complex

Direct inhibition of viral enzymes within the complex (e.g., RdRp, helicase, or protease) leading to premature chain termination, lethal mutagenesis, or the prevention of viral genome replication and polyprotein processing [3, 4, 6].