title: ATAF2, a NAC transcription factor, binds to the promoter and regulates NIT2 gene expression involved in auxin biosynthesis.
abstract: The transcription factor ATAF2, one of the plant specific NAC family genes, is known as repressor of pathogenesis-related genes and responsive to the diverse defense-related hormones, pathogen infection, and wounding stress. Furthermore, it is important to consider that tryptophan-dependant IAA biosynthesis pathway can be activated by wounding and pathogen. We found that ATAF2pro::GUS reporter was induced upon indole-3-acetonitrile (IAN) treatments. And ataf2 mutant showed reduced sensitivity to IAN whereas 35S::ATAF2 plants showed hyper-sensitivity to IAN. IAN biosynthesis required nitrilase involved in the conversion of IAN to an auxin, indole-3-acetic acid (IAA). We found that the NIT2 gene was repressed in ataf2 knockout plants. Expression of both ATAF2 and NIT2 genes was induced by IAN treatment. Transgenic plants overexpressing ATAF2 showed up-regulated NIT2 expression. ATAF2 activated promoter of the NIT2 gene in Arabidopsis protoplasts. Electrophoretic mobility shift assay revealed that NIT2 promoter region from position -117 to -82 contains an ATAF2 binding site where an imperfect palindrome sequence was critical to the protein-DNA interaction. These findings indicate that ATAF2 regulates NIT2 gene expression via NIT2 promoter binding.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea.
authors.forename: Sung Un
authors.initials: SU
authors.lastname: Huh
authors.forename: Suk-Bae
authors.initials: SB
authors.lastname: Lee
authors.forename: Hwang Hyun
authors.initials: HH
authors.lastname: Kim
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Paek
mesh_terms: D000595:Amino Acid Sequence; D000619:Aminohydrolases / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D007210:Indoleacetic Acids / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C505769:ATAF2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D007211:Indoles; D012097:Repressor Proteins; D014157:Transcription Factors; C016516:indole-3-acetonitrile; D000619:Aminohydrolases; C021867:nitrilase