Plant Molecular Biology

, Volume 50, Issue 2, pp 237–248

Molecular characterization of AtNAM: a member of theArabidopsis NAC domain superfamily

  • Manuel Duval
  • Tzung-Fu Hsieh
  • Soo Young Kim
  • Terry L. Thomas
Article

DOI: 10.1023/A:1016028530943

Cite this article as:
Duval, M., Hsieh, TF., Kim, S.Y. et al. Plant Mol Biol (2002) 50: 237. doi:10.1023/A:1016028530943

Abstract

The petunia NAM and Arabidopsis ATAF1 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.

DNA-binding domainshoot meristemtranscriptional activation

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Manuel Duval
    • 1
  • Tzung-Fu Hsieh
    • 1
  • Soo Young Kim
    • 2
  • Terry L. Thomas
    • 1
  1. 1.Department of BiologyTexas A&M UniversityCollege StationUSA
  2. 2.Kumho Life and Environmental Science LaboratoryKwang-San-Gu, KwangjuKorea