Figure 5.

Interactions and localization of carotene hydroxylases. A, BiFC detection of protein-protein interactions in maize protoplasts. CYP97A4 + CYP97C2 and HYD4 + HYD4 are interacting with each other, as seen by restored YFP fluorescence. Fusions of N-terminal and C-terminal halves of YFP with ChrD protein from cucumber (Cucumis sativus), which is known to form homodimer complexes in plastids (Libal-Weksler et al., 1997), were used as positive controls. B, Transient expression of GFP-fused proteins in maize protoplasts. CYP97 proteins are localized throughout etioplasts and concentrated at the spot of red chlorophyll autofluorescence of prolamellar bodies, as would be expected for proteins with stromal/weak peripheral membrane association. HYD4 is strictly colocalized with prolamellar bodies, consistent with integral thylakoid membrane binding. Chlorophyll, Chlorophyll autofluorescence. Bars = 10 µm.