MYC2 and MYC4 Directly Bind to the NST1 Promoter.
(A) and (B) Blue light induction of MYC2 and MYC4 expression, respectively. Arabidopsis plants (5 weeks old) were transferred to darkness for 24 h to silence expression of the light-induced genes. Then the plants were treated with blue light to examine the blue light induction of MYC2 and MYC4 expression in the inflorescence stem.
(C) Activation of the NST1 promoter by MYC2/MYC4. Left: Schematic diagram of MYC2 and MYC4 structure with amino acid lengths and the TAD and bHLH domains indicated. Right: Activation activities. Transactivation assays were performed through cotransformation of mesophyll protoplasts of Arabidopsis with pGreenII0800-NST1pro and pA7-35S-MYC2/4 constructs. VP16 is a transcriptional activator derived from herpes simplex virus protein. Three biological repeats were performed.
(D) ChIP analysis of MYC2 and MYC4 binding to the NST1 promoter fragments. Transgenic T2 Arabidopsis (4 weeks old) plants overexpressing MYC2 or MYC4 were analyzed. NST1P-F1, NST1P-F2, and NST1P-F3 represent three fragments of the NST1 promoter. Student’s t test (**P < 0.01) was used for statistical analyses; mean ± sd.