Figure 5

ISG15 expressed in the absence of HERC5 causes retention of virions on cell surfaces and in intracellular compartments. A, Transmission electron micrographs showing the plasma membrane and intracellular regions of U2OS cells that were mock transfected ("mock"), co-transfected with empty vector and pR9 ("R9 only"), or co-transfected with pR9 and CS only ("R9 + CS"). Insets show zoomed images of the dotted white boxes. Scale bars = 200 nm. B, Confocal immunofluorescence microscopy of U2OS cells mock transfected or co-transfected with pGag with or without HERC5, and the CS. Gag localization was detected using anti-p24CA (red) 48 hours post-transfection. Scale bars = 20 μm. C, Quantitative analysis of cells from part B containing punctate Gag at the plasma membrane and large intracellular clusters of Gag or intracellular diffuse/punctate Gag. Data represent the average of two independent experiments +/- SD (n = 400). ns, non-significant. ***, P < 0.0001, Fisher's exact test.