Figure 7.

GL2 Is Required for MYB23 Transcription, and GL2 Binds MYB23 L1-Box I in Yeast.

(A) to (C) Quantitative real-time PCR was performed with cDNA from 14-d-old seedling shoots with ACT7 as the reference gene. Data represent averages of three biological replicates, and normalized units are plotted on the y axis. Error bars indicate sd. Significant differences (two-tiered t test, P < 0.05) from the wild type (Col) are indicated by asterisks.

(A) HDG11 transcript is downregulated in hdg11-1 mutants.

(B) MYB23 transcript is downregulated in gl2-5 mutants.

(C) GL2 transcript is downregulated in gl2-5 mutants.

(D) The 3.1-kb MYB23 promoter region upstream of the ATG start codon contains two predicted L1-box sequences.

(E) and (F) Yeast one-hybrid analysis was performed with MYB23 promoter–derived L1-boxes I and II. Nucleotide base substitutions are indicated in lowercase for the corresponding mutant L1-boxes.

(E) GL2 but not HDG11 binds to the wild-type L1-box I but not its mutant version.

(F) Neither GL2 nor HDG11 binds to the wild-type or mutant L1-box II.