Figure 1.

Activation of the A1 and Bz1 promoters. Results of transient expression after cobombardment of cultured maize cells with different chimeras of P and C1 together with A1Luc (red) or Bz1Luc (blue) reporter constructs, in the absence (−) or presence (+) of a vector that expresses R from the constitutive CaMV 35S promoter. Sequences derived from P are shown in yellow, with the helices characteristic of each of the two Myb repeats (R2 and R3) in orange. Sequences derived from C1 are shown in gray, with the helices in green. The first two letters indicate the constitution of the Myb domain, the first indicating the constitution of R2, the second of R3; and the last indicates the origin of the C-terminal region containing the transcriptional activation motif. A UBI∷GUS construct was included in every bombardment as a normalization control. Each treatment was done in triplicate, and the data were normalized for GUS activity as described (20). The fold activation was calculated as the ratio between each particular treatment and the treatment with pA1Luc or pBz1Luc constructs without activator. The average values are shown, and the error bars indicate the standard deviation of the samples.