Putative promoter sequence of GC1. The transcriptional start site is denoted as +1, and the putative start codon (ATG) is located at +23/+25 bp. The Dof target sites, 5'-TAAAG-3' (+) or 5'-CTTTA-3'(-), which have been shown to contribute to guard-cell specific gene expression , are boxed. The ABRE, abscisic acid-response element, 5'-ACGTG-3' (+) or 5'-CACGT-3' (-), are underscored and labeled. The TATA box (5'-TATATAA-3') and the start codon (ATG) are shown in bold with dotted boxes. The arrowheads mark the positions for promoter deletion analyses in Figure 4.