Figure 3.

Arabidopsis thaliana ERD15 protein does not exhibit transactivation activity or DNA binding activity in yeast. The transactivation activities of ERD15 proteins were revealed through the expression of the lacZ reporter gene (β-galactosidase activity), detected as a blue color (shown here in dark gray/black; panels A and C), or by prototrophic growth (activation of the HIS3 reporter gene) in medium lacking histidine (His; panels B and D). Yeast AH109 cells were transformed with the indicated GAL4-BD (DNA-binding domain) chimeric constructs (panels A and B). The chimeric BD-AtERD15 neither activates β-galactosidase gene expression nor induces His prototrophy, whereas BD-GmERD15 strongly activates the expression of both reporter genes, indicating that GmERD15, but not AtERD15, exhibits transactivation activity. The same results were observed when the reporter genes were under the control of the NRP-B promoter, and the chimeras AD-AtERD15 and AD-GmERD15 were used (Panels C and D) to demonstrate that AtERD15 does not bind to the NRP-B promoter.