Figure 2. Cleavage of PABP in cells electroporated with recombinant SVs that express heterologous proteases.

(A) Cells were electroporated with transcription buffer (BHK), or wild-type SV (SV), SV-PR or SV-2A RNA and were incubated in the presence or absence of 12 μM SQ. At 8 hpe, cell extracts were analysed by Western blotting using specific antibodies against human PABP1 (10% gel). c.p., cleavage product derived from PABP in SV-PR-infected cells; MW, molecular mass (sizes given in kDa). The relative amount of intact PABP for each transfection experiment is indicated below each corresponding lane. (B) Detection of eIF4GI cleavage products by Western blotting using a mixture of antisera against its N- and C-terminal regions (7.5% gel). c.p., cleavage fragments. The amount of intact eIF4GI for each transfection experiment is indicated below each corresponding lane. (C) Detection of eIF4GII cleavage products by Western blotting using an antiserum against the C-terminal region (7.5% gel). Ct, C-terminal fragments of eIF4GII. The amount of intact eIF4GII for each transfection experiment is indicated below each lane. (D) Cleavage kinetics of PABP, eIF4GI and eIF4GII by HIV-1 protease. BHK-21 cells were electroporated as described in the Experimental section, and cell lysates were obtained at the indicated times. The values were obtained by densitometric scanning of the corresponding intact protein band at each time indicated.