Molecular Characterization of AtNAM: A Member of the Arabidopsis NAC Domain Superfamily

Plant Mol Biol. 2002 Sep;50(2):237-48. doi: 10.1023/a:1016028530943.

Abstract

The petunia NAM and ArabidopsisATAF1 and CUC2 genes define the conserved NAC domain. In petunia, loss-of-function nam mutants result in embryos that fail to elaborate shoot apical meristems (SAM), and nam seedlings do not develop shoots and leaves. We have isolated a NAC domain gene, AtNAM, from an Arabidopsis developing seed cDNA library. Expression of AtNAM mRNA is restricted primarily to the region of the embryo including the SAM. The AtNAM gene contains three exons and is located on Chromosome 1. In vivo assays in yeast demonstrate that AtNAM encodes a transcription factor and that the NAC domain includes a specific DNA binding domain (DBD). The AtNAM DBD is contained within a 60 amino acid region which potentially folds into a helix-turn-helix motif that specifically binds to the CaMV 35S promoter. The putative transcriptional activation domain is located in the C-terminal region of the protein, a highly divergent region among NAC domain-containing genes. The Arabidopsis genome contains 90 predicted NAC domain genes; we refer to these collectively as the AtNAC superfamily. The first two exons of all members of this superfamily encode the NAC domain. Most AtNAC genes contain three exons with the last exon encoding an activation domain. A subfamily of AtNAC genes contains additional terminal exons coding for protein domains whose functions are unknown.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Base Sequence
  • Binding Sites / genetics
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • DNA, Complementary / isolation & purification
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Electrophoretic Mobility Shift Assay
  • Gene Expression
  • In Situ Hybridization
  • Molecular Sequence Data
  • Multigene Family / genetics
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Protein Binding
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Saccharomyces cerevisiae / genetics
  • Seeds / genetics
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Trans-Activators / genetics

Substances

  • Arabidopsis Proteins
  • DNA, Complementary
  • DNA-Binding Proteins
  • NAM protein, Petunia hybrida
  • Plant Proteins
  • RNA, Messenger
  • Trans-Activators

Associated data

  • GENBANK/AF123311