ABP1-regulated gene expression in etiolated Arabidopsis seedlings

The AUXIN BINDING PROTEIN 1 (ABP1) is an essential plant protein involved in the control of growth and development all along the plant life. This protein was initially identified on its capacity to bind the phytohormone auxin. Binding of auxin to ABP1 was shown to enhance cell expansion of leaf cells. Conversely, the functional inactivation of ABP1 was demonstrated to severely impair cell expansion in shoot tissues. To date, the mechanism by which ABP1 controls cell expansion is still poorly understood. ABP1 was reported to affect expression of various auxin regulated genes but little is known on broader effects of ABP1 on gene expression. Here we have investigated the role of ABP1 in the control of cell expansion using dark grown hypocotyls by analyzing changes in gene expression resulting from ABP1 inactivation. Experiments were performed using the control transgenic line Alc-GUS and the SS12K9, which express GUS and ABP1, respectively, in response to ethanol treatment. Three biological repeats were prepared. RNA samples were labelled with Cy5 and Cy3 as indicated below. Samples from the SS12K9 line were compared to the corresponding control line.