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Dimerization and DNA binding of auxin response factors
Author(s) -
Ulmasov Tim,
Hagen Gretchen,
Guilfoyle Tom J.
Publication year - 1999
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1999.00538.x
Subject(s) - transcription factor , gene , palindromic sequence , amino acid , promoter , biology , auxin , dna binding protein , binding site , peptide sequence , transcription (linguistics) , genetics , dna , biochemistry , microbiology and biotechnology , palindrome , gene expression , genome , linguistics , philosophy
Summary Auxin response factors (ARFs) are transcription factors that bind with specificity to TGTCTC auxin response elements (AuxREs) found in promoters of primary/early auxin response genes. ARFs are encoded by a multi‐gene family, consisting of more than 10 genes. Ten ARFs have been analyzed by Northern analysis and were found to be expressed in all major plant organs and suspension culture cells of Arabidopsis . The predicted amino acid sequences indicate that the 10 ARFs contain a novel amino‐terminal DNA binding domain and a carboxyl‐terminal dimerization domain, with the exception of ARF3 which lacks this dimerization domain. All ARFs tested bind with specificity to the TGTCTC AuxRE, but there are subtle variations in the sequence requirements at positions 5 (T) and 6 (C) of the AuxRE. While the amino‐terminal domain of about 350 amino acids is sufficient for binding ARF1 to TGTCTC AuxREs, this domain is not sufficient for the binding of some other ARFs to palindromic AuxREs. Our results suggest that ARFs must form dimers on palindromic TGTCTC AuxREs to bind stably, and this dimerization may be facilitated by conserved motifs found in ARF carboxyl‐terminal domains. Dimerization in at least some cases may dictate which ARF(s) are targeted to AuxREs.