Figure 6.

Effect of AtCaM3 on DNA-binding activity of HSF and expression of HSP genes. A, Results of an electrophoretic mobility-shift binding assay using whole cell extracts from 10-d-old Arabidopsis plants incubated for 1 h at 22°C (C, control) or 37°C (HS). Whole cell extract was obtained from wild-type plants, three different AtCaM3-GUS-overexpressing transgenic lines (3-7, 3-21, and 3-22), and the cam3 mutant. Equal amounts (30 μg each) of whole cell protein extract were used in all lanes. Quantification of the bands is presented below the gel. B to D, Real-time RT-PCR analyses for expression of HSP genes in wild-type, cam3 mutant, three cam3/AtCaM3 transgenic lines (1-2, 7-4, and 43-1), and three AtCaM3-GUS-overexpressing transgenic lines (3-7, 3-21, and 3-22). B, Expression of AtHSP18.2. C, Expression of AtHSP25.3. D, Expression of AtHSP83. Ten-day-old seedlings were heat stressed at 37°C for 1 h. actin was used as an internal control. Samples from wild-type plants were used for normalization, with the expression level of these samples set to 1. Data are means ± se from three biological replicates. WT, Wild type.