Virus internalization assay

Primary cells or cell lines were incubated on ice with JUNV-C1, TCRV, LCMV, VSV and mNoV (MOI = 5) for 1 hr, shifted to 37°C for an additional 45 min, treated with 1 mg/ml of Proteinase K (Gibco) for 45 min on ice to strip virus from the cell surface, followed by treatment with 2mM of the inhibitor phenylmethylsulfonyl fluoride (SIGMA) to inactivate Proteinase K. Internalized viral RNA was isolated and used for RT-qPCR.