Fig. 2

Ethylene-dependent regulation of ARGOS and ARL protein levels. GFP-tagged versions of ARGOS and ARL, driven by their native promoters, were stably expressed in Arabidopsis. Transcript levels for the ARGOS-GFP and ARL-GFP fusions were determined by RT-PCR, with β-tubulin as a control. Protein levels of the GFP fusions were determined by immunoblot analysis using an anti-GFP antibody, with BiP detected by an anti-BiP antibody as a loading control. a Time course for mRNA and protein induction of ARGOS-GFP and ARL-GFP by ethylene. Seedlings were treated with 10 μL L⁻¹ for the indicated times. b Reduction in mRNA and protein levels following removal of ethylene. Expression of ARGOS-GFP and ARL-GFP was induced by ethylene treatment for 4 h, then the ethylene removed, and the kinetics for reduction followed at the RNA and protein levels. c Ethylene dose dependence for induction of ARGOS-GFP and ARL-GFP protein. Green seedlings were treated with the indicated ethylene concentrations for 4 h. Two immunoblot exposures are shown for the GFP fusions to allow for visualization of induction at low and high ethylene concentrations