FIG 2.

Furin alone is not sufficient for the efficient cleavage of MuV-F. (A) Expression levels of furin in 293T, HEK293, and Vero cells were examined by Western blotting. (B) 293T cells transfected with pCA7-MuV-F, -MuV-HN, and -EGFP or pCA7-MeV-F, pCAGGS-MeV-H, and pCA7-EGFP were observed for syncytium formation using fluorescence microscopy at 24 h posttransfection. Scale bar, 200 μm. (C) 293T and HEK293 cells were transfected with pCA7-Flag-MuV-F and pCA7-MuV-HN, or pCA7-Flag-MeV-F and pCAGGS-MeV-H. The cleavage of MuV-F or MeV-F was examined at 24 h posttransfection by Western blotting with anti-Flag ab. (D) LoVo cells were transfected with pCA7-MuV-F, -MuV-HN, and -EGFP or pCA7-MeV-F, pCAGGS-MeV-H, and pCA7-EGFP, together with indicated amounts of pCA7-furin. The cells were observed under fluorescence microscopy at 36 h posttransfection.