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Science 319 (5868): 1384-1386

Copyright © 2008 by the American Association for the Advancement of Science

TOPLESS Mediates Auxin-Dependent Transcriptional Repression During Arabidopsis Embryogenesis

Heidi Szemenyei,1,2 Mike Hannon,1,2 Jeff A. Long1*

Abstract: The transcriptional response to auxin is critical for root and vascular development during Arabidopsis embryogenesis. Auxin induces the degradation of AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) transcriptional repressors, freeing their binding partners, the AUXIN RESPONSE FACTOR (ARF) proteins, which can activate transcription of auxin response genes. We show that TOPLESS (TPL) can physically interact with IAA12/BODENLOS (IAA12/BDL) through an ETHYLENE RESPONSE FACTOR (ERF)–associated amphiphilic repression (EAR) motif. TPL can repress transcription in vivo and is required for IAA12/BDL repressive activity. In addition, tpl-1 can suppress the patterning defects of the bdl-1 mutant. Direct interaction between TPL and ARF5/MONOPTEROS, which is regulated by IAA12/BDL, results in a loss-of-function arf5/mp phenotype. These observations show that TPL is a transcriptional co-repressor and further our understanding of how auxin regulates transcription during plant development.

1 Plant Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
2 Division of Biological Sciences, Section of Cell and Developmental Biology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.

* To whom correspondence should be addressed. E-mail: long{at}salk.edu

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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Science Signaling. ISSN 1937-9145 (pre-2008: Science's STKE. ISSN 1525-8882)