Characterization of CAX-like genes in plants: implications for functional diversity

Gene. 2000 Oct 31;257(2):291-8. doi: 10.1016/s0378-1119(00)00390-5.


Transporter-mediated Ca(2+) efflux from the cytoplasm is an important component of plant signal transduction. To elucidate the diversity and role of Ca(2+)/H(+) in controlling plant cytosolic Ca(2+) concentrations, homologs of CAX (for calcium exchanger) genes were cloned from Zea mays and Arabidopsis thaliana cDNA libraries. The A. thaliana homolog of CAX (AtHCX1) is 77% identical to CAX1 while the Z. mays homolog of CAX (ZmHCX1) is 64% identical to CAX1 in amino acid sequence. AtHCX1 transcripts appeared to be expressed in all tissues, and levels of AtHCX1 RNA increased after Ca(2+) or Na(+) treatment. When expressed in yeast mutants defective in vacuolar Ca(2+) uptake, ZmHCX1 and AtHCX1 failed to suppress the Ca(2+) sensitivity of these strains. These results imply that CAX-like genes may have functions in plant ion homeostasis that differ from those of previously characterized CAX genes.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Antiporters / genetics*
  • Antiporters / physiology
  • Arabidopsis / genetics*
  • Blotting, Northern
  • Calcium-Binding Proteins / genetics*
  • Calcium-Binding Proteins / physiology
  • Cation Transport Proteins*
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • Gene Expression Regulation, Plant
  • Genes, Plant / genetics*
  • Genetic Complementation Test
  • Genetic Variation
  • Molecular Sequence Data
  • Mutation
  • Phylogeny
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Tissue Distribution
  • Zea mays / genetics*


  • Antiporters
  • Calcium-Binding Proteins
  • Cation Transport Proteins
  • DNA, Complementary
  • RNA, Plant
  • calcium-hydrogen antiporters

Associated data

  • GENBANK/AF256228
  • GENBANK/AF256229