Rapid and efficient generation of viral genome knock-in cell lines using the CRISPR-Cas9 system to produce infectious virus

Several medically significant viruses are difficult to propagate with conventional laboratory host systems, limiting their availability for detailed characterization, antiviral screening, and functional studies. A range of methods can be used to generate viruses, such as creating sophisticated cell lines, organoid cultures, and the utilization of animal models. Here, we report the generation and characterization of CRISPR-Cas9 edited Huh7 stable cell lines engineered to carry and express overlength HBV genotypes A, B, C and D and full HEV genomes in the AAVS1 site. Viral polymerase inhibitors and IFN-α significantly reduced the production of viral genomes and proteins from the edited cells. The virus released by the edited cells was infectious in permissive cell lines and could be blocked by neutralizing antibodies. This approach can extend to other viruses, like HCV genotype 3, that are hard to culture or to culturable viruses, like Dengue, for vaccine production.