Characterization of the yellow fever virus replication complex using an NS1–GFP replicon

Yellow fever virus is a mosquito-borne flavivirus responsible for severe human disease. Flaviviruses cause an estimated 400 million infections annually worldwide and are transmitted between animals and humans via arthropod vectors. Viral RNA replication is mediated by non-structural proteins that assemble into membrane-associated replication complexes (RC). Among these, the NS1 protein plays a critical role in replication complex formation and function. In this study, we investigated the replication complex of Yellow fever virus using sucrose density gradient ultracentrifugation. An NS1–GFP replicon system was constructed and employed to isolate and fractionate RC-associated components. This approach enables characterization of the molecular composition and organization of the replication complex and provides insights into the mechanisms underlying RNA replication in flaviviruses.