Figure 7.

Auxin response in Chlorophyta. A, Schematic representation of important domains of ARFs and AUX/IAAs. ARFs contain domains for the interaction with AUX-IAAs and ARFs (III and IV), an activation or repression domain (AD or RD), and a B3 DNA-binding domain (DBD). AUX-IAAs contain domains for the interaction with ARFs (III and IV), a repression domain (I), and a domain that contains a degron sequence (II). B, Effect of auxin on the expression of GLUC from the DR5 promoter in C. reinhardtii. As an example, representative data for two transgenic clones expressing the pDR5::GLUC construct (1 and 2) and one clone expressing the pDR5::NLS:GLUC construct (1) are shown. Luciferase activity was measured 7 h after auxin addition (for details, see “Materials and Methods”). No auxin-induced expression of pDR5::GLUC or pDR5::NLS:GLUC is detectable in C. reinhardtii. The luminescence units are presented as luminescence counts per second (LCPS). Control strains lacking the Luc gene had very low luminescence (0.1 LCPS per 20 μL of culture). Bars represent means of three independent experiments, and sd is indicated. [See online article for color version of this figure.]