Fig. 3. Subcellular localization of the ULT proteins. (A) Dark-field exposure of an onion epidermal cell transiently expressing an ULT1-EGFP fusion protein. The GFP signal is detected in both the nucleus (arrowhead) and the cytosol. In the cytosol, the fusion protein appears to be distributed in cytoplasmic streams (arrows). (B) Confocal image of a root from a 35S::ULT1-EGFP T2 transgenic plant. (C,D) Confocal image of a petal from a 35S::ULT1-EGFP T2 transgenic plant. (D) DAPI staining of the nuclei and cell walls in the petal shown in C. (E) An immunoblot of protein extracts from inflorescence meristem tissue, using anti-GFP serum. WT, extract from a wild type Ler plant; EGFP, extract from a 35S:EGFP transgenic plant; ULT-EGFP, extract from a 35S::ULT1-EGFP T2 transgenic plant. (F,G) Dark-field exposures of onion epidermal cells transiently expressing the ULT1-GUS-EGFP fusion protein. The GFP signal is detected in the cytosol and the perinuclear region (F) or both in the cytosol and throughout the nucleus (G). N, nucleus; CS, cytoplasmic streams.