Fig. 6.

Detection of SUC1 and Srt1 proteins in plants and yeast. (A), (B), and (E–G), Immunohistochemical stainings of 4 μm sections showing leaf veins from wt [(A) and (E)], suc2-4/pSUC2::SUC1 (line 4) (B), suc2-5 (F), and suc2-5/pSUC2::srt1 (line 18) (G) plants. Green fluorescence of anti-rabbit-Cy2 in CCs corresponds to αSUC1 [(A) and (B)] or αSrt1 [(E–G)]. Red fluorescence of anti-mouse-Cy3 corresponds to anti-RS6 labelling of sieve elements. For (A), (E), and (F) the images of the fluorescence signals were merged with the corresponding bright field images. Yellow staining in (A), (B), and (G) shows xylem autofluorescence. (C) Western blot analyses using αSrt1 to detect the 60 kDa Srt1 protein in extracts from yeast strain SEY2102 (Emr et al., 1983) (N, control yeast cells transformed with the empty vector; Srt1, yeast cells expressing srt1) or in extracts from source leaves of wt/pSUC2::srt1 (KW48), wt/p35S::srt1 (KW41), and wt plants (m, membrane fraction; s, soluble fraction). The red arrowhead shows the weak Srt1-derived signal in wt/pSUC2::srt1 plants. (D) Immunostaining of 4 μm sections of srt1-expressing yeast cells. Green fluorescence of anti-rabbit-Cy2 corresponds to αSrt1. Yellowish colour in (A), (B), (E), and (G) shows autofluorescence of cell-wall phenolic compounds in xylem vessels. Bars=5 μm.