Aux/IAA proteins repress expression of reporter genes containing natural and highly active synthetic auxin response elements.
A highly active synthetic auxin response element (AuxRE), referred to as DR5, was created by performing site-directed mutations in a natural composite AuxRE found in the soybean GH3 promoter. DR5 consisted of tandem direct repeats of 11 bp that included the auxin-responsive TGTCTC element. The DR5 AuxRE showed greater auxin responsiveness than a natural composite AuxRE and the GH3 promoter when assayed by transient expression in carrot protoplasts or in stably transformed Arabidopsis seedlings, and it provides a useful reporter gene for studying auxin-responsive transcription in wild-type plants and mutants. An auxin response transcription factor, ARF1, bound with specificity to the DR5 AuxRE in vitro and interacted with Aux/IAA proteins in a yeast two-hybrid system. Cotransfection experiments with natural and synthetic AuxRE reporter genes and effector genes encoding Aux/IAA proteins showed that overexpression of Aux/IAA proteins in carrot protoplasts resulted in specific repression of TGTCTC AuxRE reporter gene expression.
Ulmasov
T
T
Department of Biochemistry, University of Missouri, Columbia 65211, USA.
Murfett
J
J
Hagen
G
G
Guilfoyle
T J
TJ
D017360:Arabidopsis / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D017930:Genes, Reporter; D005966:Glucuronidase / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D010940:Plant Proteins / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014162:Transfection
D007210:Indoleacetic Acids; D010940:Plant Proteins; D005966:Glucuronidase