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. 2003 Dec;133(4):1779–1790. doi: 10.1104/pp.103.030742

Figure 2.

Figure 2.

Diurnal regulation of XSP30 gene expression and XSP30 content of xylem sap. A and B, Time course of XSP30 expression. Cucumber plants were grown under a 16-h light/8-h dark photoperiod. Total RNA (10 μg lane-1) was extracted from the roots of seedlings every 4 h, beginning on the 11th d after sowing. RNA samples were subjected to RNA gel-blot analysis with XSP30 cDNA and rRNA probes. Shown are the original autoradiograph in A and the ratio of the intensity of hybridization of XSP30 and rRNA in B. C through E, Detection of XSP30 protein in xylem sap. Xylem sap was collected at 4-h intervals from stems of cucumber plants 30 d after sowing. The proteins in equal volumes of sap (5 μL lane-1) were separated by SDS-PAGE and detected with anti-XSP30 serum on nylon membranes (C) or silver stained (D). The ratio of the intensity of the XSP30 signal and staining of the total proteins is shown in E. The XSP30 gene expression in cucumber roots, 30 d after sowing, is shown in F. Total RNA (10 μg lane-1) was extracted from the roots of seedlings every 8 h, beginning on d 30 after sowing. RNA samples were subjected to RNA gel-blot analysis with an XSP30 cDNA and a ubiquitin fragment as probes. The original autoradiograph and the ratio of the intensity of hybridization to the XSP30 and ubiquitin transcripts are shown. Dawn was defined as zeitgeber time 0. The periods of light and dark are indicated as shaded and black bars, respectively.