Figure 9.

BZR1 Has a Similar Accumulation Pattern as DLT in Rice.

BZR1 protein was detected by immunoblotting with anti-Os BZR1 antibody. Rice HSP, which was detected with anti-HSP antibody, was used as the internal reference indicating equal loading of proteins.

(A) Differential accumulation pattern of BZR1 between young and mature leaves. Young, 4-d-old seedling leaves. Mature, fully expanded flag leaves.

(B) Induction of BZR1 protein accumulation by BL treatment in rice. Four-day-old d2 seedlings were used for the treatment.

(C) Comparison of BZR1 protein level and form in the wild type (WT), Gi, and Go. Go-s represents a GSK2-1 overexpression line with severe phenotypes. Mature leaves were used for the analysis.

(D) Proposed working model for GSK2, BZR1, and DLT. BR induces protein accumulation of BZR1 and DLT through repressing GSK2 activity. GSK2 inhibits both BZR1 and DLT by phosphorylation. BZR1 can bind to the DLT promoter to repress DLT transcription.

(E) A hypothetical model of the BR signal magnification mechanism. Multiple substrates of BIN2/GSK2 may act redundantly, specifically, or competitively to mediate various BR responses.