Genome-scale CRISPR screen identifies host factors associated with bovine parainfluenza virus 3 infection

Bovine parainfluenza virus type 3 (BPIV-3) is a major pathogen associated with the bovine respiratory disease complex. However, the limited understanding of host factors crucial for BPIV-3 replication has hindered the development of effective preventive and therapeutic strategies. To tackle this critical issue, we constructed a bovine genome-wide CRISPR/Cas9 knockout library in Madin-Darby bovine kidney cells, which was then used to systematically identify and characterize the host genes essential for BPIV-3a replication. Subsequently, 10 genes were validated using both RT-qPCR and viral titration assays. Furthermore, through gene knockout or knockdown and rescue experiments, we identified three key genes required for BPIV-3a replication: Wnt family member 5A (WNT5A), solute carrier family 16 member 13 (SLC16A13), and selenoprotein N (SELENON). However, their effects on viral adhesion and internalization varied. WNT5A was involved in both processes, SLC16A13 participated solely in internalization, while SELENON had no significant impact on either. Beyond BPIV-3a, these three genes were also found to be essential for the infection of BPIV-3c and Bovine enterovirus. In conclusion, this study offers novel insights into the molecular mechanisms governing the replication and pathogenesis of BPIV-3a, BPIV-3c, and bovine enterovirus within host cells, thereby providing a foundation for identifying potential targets in the development of novel antiviral strategies.