Plant Transcription factor database - Universität Potsdam
version: 3.0

AUX/IAA Family


Tiwari et al. 2004: Aux/IAA proteins are short-lived nuclear proteins that repress expression of primary/early auxin response genes in protoplast transfection assays. Repression is thought to result from Aux/IAA proteins dimerizing with auxin response factor (ARF) transcriptional activators that reside on auxin-responsive promoter elements, referred to as AuxREs. Most Aux/IAA proteins contain four conserved domains, designated domains I, II, III, and IV. Domain II and domains III and IV play roles in protein stability and dimerization, respectively. A clear function for domain I had not been established. Results reported here indicate that domain I in Aux/IAA proteins is an active repression domain that is transferable and dominant over activation domains. An LxLxL motif within domain I is important for conferring repression. The dominance of Aux/IAA repression domains over activation domains in ARF transcriptional activators provides a plausible explanation for the repression of auxin response genes via ARF-Aux/IAA dimerization on auxin-responsive promoters.

Members of this family
  SHOULD possess AUX_IAA domain
  SHOULD NOT possess Auxin_resp B3 domains

Domain alignments

Benchmark against A. thaliana

The Sensitivity and Positive Predictive Value (PPV) were assessed for this family. The data reported by Remington et al. 2004 for A. thaliana were taken as gold standard.

The gold standard reported 29 members for this family, 28 of which are present in ArabTFDB, giving a PPV of 1.00. One additional member not present in ArabTFDB might be a false negative, giving a Sensitivity of 0.97.

This family is also present in:


General references

Liscum, E; Reed, JW. 2002. Genetics of Aux/IAA and ARF action in plant growth and development. Plant Mol. Biol. 49(3-4):387-400 PUBMEDID:12036262
Tiwari, SB; Hagen, G; Guilfoyle, TJ. 2004. Aux/IAA proteins contain a potent transcriptional repression domain. Plant Cell 16(2):533-43 PUBMEDID:14742873
Tiwari, SB; Wang, XJ; Hagen, G; Guilfoyle, TJ. 2001. AUX/IAA proteins are active repressors, and their stability and activity are modulated by auxin. Plant Cell 13(12):2809-22 PUBMEDID:11752389