PPIA and infection: Of particular note, knockdown of IGF2BP1-associated proteins (IGF2BP1 and YBX1)37 reduced the vRNA levels for both SARS-CoV-2 and ZIKV (Fig. 4a, b), as did knockdown of PPIA, a protein known to bind with vRNA during infection.38 Some proteins exerted opposing trends for the two viruses.