The cleaved P74-N and P74-C-Flag subunits associate with the PIF complex after cleavage. Ac-Rep-P74-Flag L-ODVs were released from Se-L-OBs and purified through a sucrose gradient. ODV membrane proteins were extracted for co-IP analysis. Co-IP was performed with PIF1 antiserum and with preimmune serum as a negative control. Co-IP input and eluate were separated by 10% SDS-PAGE followed by Western analysis with P74 PAb, Flag PAb, or PIF1 or PIF2 antibodies. To show the position of full-length P74-Flag, L-ODVs were purified from heated L-OBs and detected with Flag PAb. Positions of the full-length P74-Flag, P74-N, P74-C-Flag, PIF1, PIF2, and IgG heavy chain are indicated by arrows. (A) Co-IP results with PIF1 antibody. (B) Co-IP results with PIF1 preimmune serum.