Athb-12, a homeobox-leucine zipper domain protein from Arabidopsis thaliana, increases salt tolerance in yeast by regulating sodium exclusion

Biochem Biophys Res Commun. 2004 Oct 15;323(2):534-40. doi: 10.1016/j.bbrc.2004.08.127.


An Arabidopsis cDNA clone that encodes Athb-12, a homeobox-leucine zipper domain protein (HD-Zip), was isolated by functional complementation of the NaCl-sensitive phenotype of a calcineurin (CaN)-deficient yeast mutant (cnbDelta, regulatory subunit null). CaN, a Ca2+/calmodulin-dependent protein phosphatase, regulates Na+ ion homeostasis in yeast. Expression of Athb-12 increased NaCl tolerance but not osmotic stress tolerance of these cnbDelta cells. Furthermore, expression of two other HD-Zip from Arabidopsis, Athb-1 and -7, did not suppress NaCl sensitivity of cnbDelta cells. These results suggest that Athb-12 specifically functions in Na+ ion homeostasis in yeast. Consistent with these observations, expression of Athb-12 in yeast turned on transcription of the NaCl stress-inducible PMR2A, which encodes a Na+/Li+ translocating P-type ATPase, and decreased Na+ levels in yeast cells. To investigate the biological function of Athb-12 in Arabidopsis, we performed Northern blot analysis. Expression of Athb-12 was dramatically induced by NaCl and ABA treatments, but not by KCl. In vivo targeting experiments using a green fluorescent protein reporter indicated that Athb-12 was localized to the nucleus. These results suggest that Athb-12 is a putative transcription factor that may be involved in NaCl stress responses in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cells, Cultured
  • Cloning, Molecular
  • Drug Tolerance / physiology
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Leucine Zippers / genetics
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / drug effects*
  • Saccharomyces cerevisiae / physiology*
  • Sodium / metabolism*
  • Sodium Chloride / pharmacology*
  • Tissue Distribution
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Water-Electrolyte Balance / drug effects
  • Water-Electrolyte Balance / physiology*


  • Arabidopsis Proteins
  • Homeodomain Proteins
  • Recombinant Proteins
  • Transcription Factors
  • atHB-12 protein, Arabidopsis
  • Sodium Chloride
  • Sodium