Figure 3.

GRF Transcription Factors Are DELLA Interactors and GRF Expression Is GA-Regulated in the Cold.

(A) Venn diagram showing the overlap between all 370 previously identified DELLA interactions and the 438 cold-regulated genes whose expression is GA- and cold-regulated.

(B) Graphs displaying fragments per kilobase million (FPKM) values of GRF gene expression of seedlings grown in ambient temperature (21°C) and in cold stress (4°C) in the absence (mock) and presence of 100 µM GA₃. Shown are means and sd of three biological replicate samples from pooled seedling shoots.

(C) Targeted yeast two-hybrid interaction analysis between eight of the nine Arabidopsis GRF proteins and GAI as well as RGA together with the respective empty vector controls. AD, activation domain; DB, DNA-binding domain.

(D) and (E) Results of BiFC experiments performed in transiently transformed N. benthamiana leaf epidermal cells between full-length DELLA proteins (GAIFL and RGAFL; [D]) and N-terminally truncated DELLA proteins (GAI141 and RGA204; [E]) with interaction candidates as specified. XERICO is a biologically unrelated protein that serves as a negative control (Ko et al., 2006).