TCP4-dependent induction of CONSTANS transcription requires GIGANTEA in photoperiodic flowering in Arabidopsis
Fig 6
TCP4 physically interacts with GI.
(A) Protein-protein interaction between TCP4 and GI was analyzed in yeast. Full-length TCP4 and full-length or truncated GI fused to the DNA-binding domain (DBD) or the activation domain (AD) of Gal4 were tested under selective [–LWH (top),–LWH+10 mM 3-aminotriazole (3-AT, middle)] and non-selective [–LW (bottom)] conditions. For GI, N and C indicate the amino acid residues 1–391 and 382–1173, respectively. (B) Subcellular localization of TCP4 fused to enhanced YFP (TCP4-YFP) was observed in N. benthamiana epidermal cells. H2B-RFP was used for the nuclear marker. Images from YFP and RFP channels were merged with bright-field (BF) images. (C) BiFC assays of interaction between mTCP4 and GI are shown. The full-length of mTCP4 fused to the N-terminal half of enhanced YFP (YFPn-mTCP4) and the full-length of GI fused to the C-terminal half of enhanced YFP (YFPc-GI) were co-expressed in N. benthamiana leaf epidermal cells. Nuclear-localized form of GST fragment (GSTNLS) fused to YFPn or YFPc was used as negative control. Scale bar, 20 μm. (D) Co-immunoprecipitation (Co-IP) assay of HA-mTCP4 and GI-3F6H was performed. Proteins were expressed in N. benthamiana.