FIG. 6.

Overexpression of underphosphorylated 4E-BP1 protein impairs human coronavirus infection. HeLa cells were transfected with plasmid pcDNA3-HA-4E-BP1 wt (A) or pcDNA3-HA-4E-BP1 4A (B), and 36 h posttransfection, the cells were mock or coronavirus infected. At the indicated hpi, cells were used for immunofluorescence using antibodies against HA to monitor plasmid transfection and S protein to monitor coronavirus infection. Asterisks indicate transfected and infected cells. # indicates cells that were transfected but uninfected. DAPI, 4′,6′-diamidino-2-phenylindole. (C) Quantitation of the efficiency of infection in untransfected cells (−) and in pcDNA3-HA-4E-BP1 wt (WT)- or pcDNA3-HA-4E-BP1 4A (4A)-transfected cells subsequently infected with influenza virus (data not shown) or human coronavirus HCoV-229E.