The Arabidopsis tandem zinc finger protein AtTZF1 affects ABA- and GA-mediated growth, stress and gene expression responses

Plant J. 2011 Jan;65(2):253-68. doi: 10.1111/j.1365-313X.2010.04419.x. Epub 2010 Dec 8.


Tandem zinc finger (TZF) proteins are characterized by two zinc-binding CCCH motifs arranged in tandem. Human TZFs such as tristetraproline (TTP) bind to and trigger the degradation of mRNAs encoding cytokines and various regulators. Although the molecular functions of plant TZFs are unknown, recent genetic studies have revealed roles in hormone-mediated growth and environmental responses, as well as in the regulation of gene expression. Here we show that expression of AtTZF1 (AtCTH/AtC3H23) mRNA is repressed by a hexokinase-dependent sugar signaling pathway. However, AtTZF1 acts as a positive regulator of ABA/sugar responses and a negative regulator of GA responses, at least in part by modulating gene expression. RNAi of AtTZF1-3 caused early germination and slightly stress-sensitive phenotypes, whereas plants over-expressing AtTZF1 were compact, late flowering and stress-tolerant. The developmental phenotypes of plants over-expressing AtTZF1 were only partially rescued by exogenous application of GA, implying a reduction in the GA response or defects in other mechanisms. Likewise, the enhanced cold and drought tolerance of plants over-expressing AtTZF1 were not associated with increased ABA accumulation, suggesting that it is mainly ABA responses that are affected. Consistent with this notion, microarray analysis showed that over-expression of AtTZF1 mimics the effects of ABA or GA deficiency on gene expression. Notably, a gene network centered on a GA-inducible and ABA/sugar-repressible putative peptide hormone encoded by GASA6 was severely repressed by AtTZF1 over-expression. Hence AtTZF1 may serve as a regulator connecting sugar, ABA, GA and peptide hormone responses.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Abscisic Acid / metabolism*
  • Abscisic Acid / pharmacology
  • Abscisic Acid / physiology
  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis / physiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cold Temperature
  • Droughts
  • Gene Expression
  • Gene Expression Regulation, Plant*
  • Germination
  • Gibberellins / metabolism*
  • Gibberellins / pharmacology
  • Gibberellins / physiology
  • Glucose / metabolism
  • Hexokinase / metabolism
  • Microarray Analysis
  • Plant Growth Regulators / metabolism*
  • Plant Growth Regulators / pharmacology
  • Plant Growth Regulators / physiology
  • Plants, Genetically Modified
  • RNA Interference
  • RNA, Plant / metabolism
  • Seeds / growth & development
  • Seeds / physiology
  • Signal Transduction / physiology
  • Stress, Physiological
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • Arabidopsis Proteins
  • Gibberellins
  • Plant Growth Regulators
  • RNA, Plant
  • TZF1 protein, Arabidopsis
  • Transcription Factors
  • Abscisic Acid
  • gibberellic acid
  • Hexokinase
  • Glucose