Fig. 4

Characterization of DUO1 transcription factor activity. a Amino acid sequence alignment of regions A, B, and C among AtDUO1, MpDUO1, and MpR2R3-MYB21 (top). Dots indicate matching residues with AtDUO1. Asterisks indicate putative DNA-interacting residues in region C. Structural modeling of MpDUO1 in complex with DNA using SWISS-MODEL (bottom). The MpDUO1 MYB domain is overlaid onto the structure of the AMV v-MYB-DNA complex (PDB code: 1H8A). b in vivo transcriptional activation potentials of MpDUO1 and chimeras. Schematic diagram of constructs (left) are color-coded light blue (AtDUO1), dark blue (MpDUO1), and orange (MpR2R3-MYB21). DUO1 transcriptional activation potentials were measured by relative luciferase activity (right). n = 4 (upper), n = 8 (lower) (**p < 0.01; *p < 0.05; ns not significant; Student’s t-test). c Position weight matrix representations of the top-scoring 8-mer DNA sequences bound by different MYB domains on a protein-binding DNA microarray. Numbers denoted on the right side of each motif represent the motif E- and Z-scores¹⁹