Encapsulating quantum dots into enveloped virus in living cells for tracking virus infection

Utilization of quantum dots (QDs) for single virus tracking has attracted growing interest. Through modification of viral surface proteins, viruses can be labeled with various functionalized QDs and used for tracking the routes of viral infections. However, incorporation of QDs on the viral surface may affect the efficiency of viral entry and alter virus-cell interactions. Here, we describe that QDs can be encapsulated into the capsid of vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped lentivirus (PTLV) in living cells without modification of the viral surface. QDs conjugated with modified genomic RNAs (gRNAs), which contain a packaging signal (Psi) sequence for viral genome encapsulation, can be packaged into virions together with the gRNAs. QD-containing PTLV demonstrated similar entry efficiency as the wild-type PTLV. After infection, QD signals entered the Rab5+ endosome and then moved to the microtubule organizing center of the infected cells in a microtubule-dependent manner. Findings in this study are consistent with previously reported infection routes of VSV and VSV-G pseudotyped lentivirus, indicating that our established QD packaging approach can be used for enveloped virus labeling and tracking.