Fig 6.
The protease activity of FMDV 3Cpro is required for inhibition of intra-Golgi transport. Vero cells coexpressing VSV TsO45 G protein fused to YFP and 3Cpro were incubated at 40°C for 40 h and cooled to 32°C for the indicated times (0, 0.5, and 3 h). (A) Cells expressing VSV TsO45 G-YFP (i, iv, and vii) and inactive 3Cpro fused to mCherry (iii, vi, and ix) were immunostained for endoplasmic reticulum (ERp57, ii) or Golgi compartment (β-COP, v). Delivery of the G protein to the plasma membrane was assessed by adding I1 antibody before permeabilization (I1, viii). (B) Cells expressing VSV TsO45 G-YFP (i and iv) and active 3Cpro fused to mCherry (iii and vi) were immunostained at 3 h for Golgi compartment (β-COP, ii). Delivery of the G protein to the plasma membrane at 3 h was assessed by adding I1 antibody before permeabilization (I1, v). The arrowhead shows a cell expressing active 3Cpro (vi) and VSVG-YFP (iv) which lacks I1 staining (v) at 3 h.