Figure 6.

pex7-2 defects in matrix protein import. (A) Cotyledons of 7-d-old light-grown seedlings or of seedlings grown 1 d in light and 4 d in darkness on 0.5% sucrose were analyzed using confocal fluorescence microscopy. PTS2 protein targeting was visualized by imaging fluorescence from a GFP derivative (PTS2-GFP) carrying the N-terminal peroxisome targeting signal from PED1 (Woodward and Bartel, 2005) in epidermal cells (first column) and the underlying mesophyll cells (second column). The mesophyll column shows merged images of GFP (green) and chlorophyll (chl; magenta) fluorescence. The large central vacuole of expanded plant cells consolidates most of the cytosol at the cell margins. Dark-grown cotyledons were briefly stained with propidium iodide, which stains cell walls, before visualization of epidermal cells; the last column shows merged image of GFP (green; third column) and propidium iodide (magenta) fluorescence. Bar, 20 μm. (B) Cotyledons of seedlings grown as described in A were analyzed as described in A. PTS1 protein targeting was visualized by imaging fluorescence from a GFP derivative (GFP-PTS1) carrying a C-terminal PTS1 (Zolman and Bartel, 2004). Bar, 20 μm.