In vitro investigation of host Synaptogyrin-2 role in BVDV-1 replication

Bovine viral diarrhea virus type 1 (BVDV-1) is an RNA virus known for lifelong persistent infection in affected animals and substantial economic impact in cattle. While current approaches of infection control rely on biosecurity and immunization, recent advances in genome editing provide opportunities for improving genetic resistance of livestock to viral diseases. Any improvements in our understanding of the role of host genes in viral replication could lead to new gene-editing applications, supporting future efforts to control BVDV-1 worldwide. Recent evidence demonstrates that Synaptogyrin-2 (SYNGR2) gene plays a role in the replication of DNA and RNA viruses across different hosts, from humans to pigs. Given the functions of SYNGR2 in pathogen entry and viral replication, this study aimed to assess the role of this gene in BVDV-1 infection. The BVDV-1 strain used in the study was propagated in Madin-Darby bovine kidney (MDBK) cells and sequenced using Oxford Nanopore Technology. The sequencing reads were subjected to de novo genome assembly, exhibiting substantial similarity with Singer Arg BVDV-1 strain (97.75%). A SYNGR2 knock-out (KO) MDBK clone was generated via CRISPR-Cas9 gene editing. The KO clone included a 163 bp deletion in the mRNA of the SYNGR2 gene, predicted to result in a shift in the reading frame starting after residue 118, affecting the second intraluminal loop and the carboxyl terminal domain. There was no difference in viral replication between wild type and SYNGR2 KO MDBK clone, measured in cells (P > 0.08) and supernatant (P > 0.21), suggesting that SYNGR2 is less likely critical for the replication of BVDV-1. Our findings could be a result of key differences from previous findings that involved SYNGR2 in the replication of DNA and RNA viruses, emphasizing the need for exploring in more detail the role of host genes in BVDV-1 replication and pathogenesis.