S100A6 and infection: As shown in Figure 6D, except for PRAAll, all PRA mutants bearing single mutations demonstrated increased PRRSV-SD16 infection by measuring RNA expression level of PRRSV-N as compared to wild-type PRA in MARC-145 cells, which was consistent with results from N protein-level (Figure 6E) and absolute quantification of viral RNA copies in cell supernatants (Figure 6F).