Structural highlights
Function
ARFA_ARATH Auxin response factors (ARFs) are transcriptional factors that binds specifically to the DNA sequence 5'-TGTCTC-3' found in the auxin-responsive promoter elements (AuxREs). Seems to act as transcriptional repressor. Formation of heterodimers with Aux/IAA proteins may alter their ability to modulate early auxin response genes expression. Promotes flowering, stamen development, floral organ abscission and fruit dehiscence. Acts as repressor of IAA2, IAA3 and IAA7.[1] [2]
Publication Abstract from PubMed
Auxin regulates numerous plant developmental processes by controlling gene expression via a family of functionally distinct DNA-binding auxin response factors (ARFs), yet the mechanistic basis for generating specificity in auxin response is unknown. Here, we address this question by solving high-resolution crystal structures of the pivotal Arabidopsis developmental regulator ARF5/MONOPTEROS (MP), its divergent paralog ARF1, and a complex of ARF1 and a generic auxin response DNA element (AuxRE). We show that ARF DNA-binding domains also homodimerize to generate cooperative DNA binding, which is critical for in vivo ARF5/MP function. Strikingly, DNA-contacting residues are conserved between ARFs, and we discover that monomers have the same intrinsic specificity. ARF1 and ARF5 homodimers, however, differ in spacing tolerated between binding sites. Our data identify the DNA-binding domain as an ARF dimerization domain, suggest that ARF dimers bind complex sites as molecular calipers with ARF-specific spacing preference, and provide an atomic-scale mechanistic model for specificity in auxin response.
Structural Basis for DNA Binding Specificity by the Auxin-Dependent ARF Transcription Factors.,Boer DR, Freire-Rios A, van den Berg WA, Saaki T, Manfield IW, Kepinski S, Lopez-Vidrieo I, Franco-Zorrilla JM, de Vries SC, Solano R, Weijers D, Coll M Cell. 2014 Jan 30;156(3):577-89. doi: 10.1016/j.cell.2013.12.027. PMID:24485461[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hagen G, Guilfoyle T. Auxin-responsive gene expression: genes, promoters and regulatory factors. Plant Mol Biol. 2002 Jun-Jul;49(3-4):373-85. PMID:12036261
- ↑ Ellis CM, Nagpal P, Young JC, Hagen G, Guilfoyle TJ, Reed JW. AUXIN RESPONSE FACTOR1 and AUXIN RESPONSE FACTOR2 regulate senescence and floral organ abscission in Arabidopsis thaliana. Development. 2005 Oct;132(20):4563-74. Epub 2005 Sep 21. PMID:16176952 doi:http://dx.doi.org/dev.02012
- ↑ Boer DR, Freire-Rios A, van den Berg WA, Saaki T, Manfield IW, Kepinski S, Lopez-Vidrieo I, Franco-Zorrilla JM, de Vries SC, Solano R, Weijers D, Coll M. Structural Basis for DNA Binding Specificity by the Auxin-Dependent ARF Transcription Factors. Cell. 2014 Jan 30;156(3):577-89. doi: 10.1016/j.cell.2013.12.027. PMID:24485461 doi:http://dx.doi.org/10.1016/j.cell.2013.12.027
