Fig. 4

Binding of SAG202 to the ICS1 promoter truncations and mutants in yeast and in planta. (a) Binding of SAG202 to the ICS1 promoter truncations. The LacZ reporter gene driven by various ICS1 promoter truncations was used to test binding ability of the GAD-SAG202 fusion protein. Red dash lines indicate the 104 bp promoter region containing the SAG202 binding sequence. The ICS2 promoter (1626 bp in length) was also tested. (b) Failure of SAG202 binding to the ICS1 promoter that contains either transversion mutation or deletion of the motif sequence GAAATT (red letters) within the 104 bp region in yeast cells. (c) GUS staining of senescent leaves in transgenic Arabidopsis plants (WT or sag202 mutant background) harboring P_ICS1W-GUS (_W for WT), P_ICS1T-GUS (_T for transversion; the promoter contains the transversion mutation shown in b) or P_ICS1D-GUS (_D for deletion; the promoter contains the deletion mutation shown in b). (d) GUS enzymatic activities (expressed as nmol methylumbelliferone produced min ^− 1 mg ^− 1 protein) of senescent leaves of transgenic plants shown in c. Data are mean values ± SD of five samples. Significant (P > 0.05) differences between means are indicated by different letters. ANOVA analysis with LSD test was used