| Abstract Detail
Hormone Biology Sungur, Can [1], Schultz, Erica [2], Miller, Sarah [3], Bergholtz, Johann [3], Brisbois, Ronald [2], Hoye, Becky [2], Overvoorde, Paul [4]. Small Molecule Perturbation of Auxin Responses in Arabidopsis thaliana. Despite recent advances in our understanding of auxin signaling, additional components required for auxin-mediated processes remain unidentified. Chemical genetics offers a powerful approach to manipulate plant hormone action. Identification of small molecules that perturb a signaling pathway can lead to the isolation of the cellular targets of these compounds and their role in mediating signaling can be tested. This approach has previously been used to identify and initially characterize compounds A, B, C, and D, which attenuate the auxin-inducible expression of the BA3-GUS reporter gene (Armstrong et al., P.N.A.S 101: 14978). As an outgrowth of efforts to provide multi-disciplinary, research-based opportunities for undergraduate students, we have performed a structure-function analysis of compound A, a furyl acrylate ester of a thiadiazole heterocycle. In order to determine what components of this molecule are required for activity we synthesized a series of derivates and then tested them for their ability to block auxin-induced BA3-GUS expression, alter root elongation, change the rate of gravitropic response, attenuate the high-temperature stimulation of hypocotyl elongation, and decrease the turnover rate of AXR3/IAA17-GUS protein. Based on these analyses, we conclude that when applied to plants the ester linkage of compound A is hydrolyzed to release the active core moiety of this molecule, 2-furylacrylic acid (2-FAA). This molecule does not block the association of GST-IAA7 with myc-TIR1 in immunoprecipitation experiments and does not promote this interaction by itself. Further tir1, afb1, afb2, afb3, and axr2 seedlings respond like wild type to the presence of this compound. Additional experiments to characterize the cellular target of 2-FAA will be presented.
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1 - Macalester College, Department of Biology, 1600 Grand Ave., St. Paul, MN, 55105, U.S.A.
2 - Macalester College, Department of Chemistry
3 - Macalester College, Departments of Biology and Chemistry
4 - Macalester College, Department of Biology
Keywords:
auxin
chemical genetics.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P35045
Abstract ID:2455 |
