Fig. 3. Analysis of the de novo formation of caveolae in mammalian cells. (A) Wild-type MEFs were labelled with anti-Cav1 (green) and anti-GM130 (red) antibodies and prepared for confocal microscopy or surface-labelled with CTB-HRP and prepared for electron microscopy. (B-E) Using identical methodology, Cav1-null MEFs injected with HRP and either HsCav1-HA (B), MmCav3-HA(C) AmCav-HA DNA (D) and CeCav-a-HA (E) and were prepared for both confocal and electron microscopy. All transiently expressed constructs, except CeCav-a-HA had the same subcellular distribution as Cav1 in wild-type MEFs as determined by confocal microscopy and produced surface-connected caveolae as identified with electron microscopy. Injected cells were identified by electron-dense HRP-DAB labelling of the nucleus. Scale bars: 10 µm (confocal images), 200 nm (EM images).