Live Visualization of HIV-1 Proviral DNA Using a Dual-Color-Labeled CRISPR System.

HIV latency is one of the major problems in HIV/AIDS cure. Imaging single-copy integrated proviral HIV DNA in host cell has both virology and clinical significance but remains technical challenge. Here, we developed a dual-color labeled CRISPR system to image the HIV-1 integrated proviral DNA in latently infected cells. The pair of CRISPRs was fluorescently labeled with two different color QDs using two alternative bioorthogonal ligation reactions. Integrated HIV-sequences are successfully mapped based on the colocalized signals of QDs in living cells. Compared to the existing zinc finger proteins and TALENs, the CRISPR system is much easier to operate and more efficient in imaging of internal genomic loci. Therefore, the proposed method could be not only a powerful tool for imaging proviral HIV-1, but also a versatile platform to image single genomic loci in living cells.