Figure 5

Cellular localization of endogenous OAS1 p42 in HeLa and p46 in Daudi cells. (A) Daudi cells and (B) HeLa cells were treated with IFN-β for 24 hours. The cells were fixed and prepared for immunofluorescence microscopy (upper panels), which was carried out with the anti-OAS1 antibody and a FITC-conjugated secondary antibody (green). p46 OAS1 was detected in Daudi cells and mainly p42 OAS1 in HeLa cells. Red fluorescence shows the localization of the mitochondrial specific protein VDAC1. Yellow fluorescence indicates the degree of co-localization between the OAS1 proteins and the mitochondrial protein in the merged pictures. Electron microscopy (lower panels) shows localization of the p46 OAS1 protein in Daudi cells and mainly p42 in HeLa cells. Gold particle labeling demonstrates the localization of the OAS1 proteins. Black arrows indicate OAS1 proteins in the mitochondria and red arrows OAS1 proteins in vacuoles/lysosomes in the cytoplasm. The white bars are 10 μm and the black bars 0.5 μm. N: the nucleus. G: Golgi apparatus.