H1N1 SIV replication is increased in Plscr1 knockout mice
In order to investigate the functions of PLSCR1 during Influenza A virus infection in vivo , we developed Plscr1 knockout mice using CRISPR/Cas9 genome editing technique. The mouse Plscr1 gene contains eight exons encoding 378 amino acids, and two sgRNAs were designed to target exon 4 (Figure 2A). DNA sequencing revealed that a deletion of 122 bp was introduced into exon 4 in Plscr1 knockout mice, which causes a premature translational stop and gives rise to a potentially truncated protein of 43 amino acids (Figure 2B). RT-PCR, western blot, and immunohistochemistry results confirm that PLSCR1 expression is indeed disrupted in the homogenous knockout mice (Figures 2C-2E). Interbreeding of Plscr1+/− mice gave rise to offspring in the expected Mendelian ratio (23.8% wild-type, 47.6% Plscr1+/− , and 28.6%Plscr1-/- ; n=42) with normal viability, suggesting that PLSCR1 is dispensable for general development in mice.