Fig. 3.

Nipah F-mediated membrane fusion in cathepsin L+/+ and cathepsin L−/− MEFs. pCAGGS-Nipah F and Nipah G and a T7-luciferase reporter gene plasmid with or without pSG5-cathepsin L vector were transfected into MEFs. MEFs were overlaid with T7 polymerase-expressing BSR cells and the mixed cell populations incubated for 3 h at 37 °C. Cells were lysed and luciferase activity measured on a luminometer. Background values were ascribed to cells expressing only the attachment protein Nipah G and then subtracted from the values for Nipah F and F + G ± cathepsin L. The results presented are representative of six separate experiments.