title: Identification of Arabidopsis histone deacetylase HDA6 mutants that affect transgene expression.
abstract: A mutant screen was conducted in Arabidopsis that was based on deregulated expression of auxin-responsive transgenes. Two different tightly regulated (i.e., very low expression in the absence of auxin treatment and very high expression after exogenous auxin treatment) auxin-responsive promoters were used to drive the expression of both a beta-glucuronidase (GUS) reporter gene and a hygromycin phosphotransferase (HPH)-selectable marker gene. This screen yielded several mutants, and five of the mutations (axe1-1 to axe1-5) mapped to the same locus on chromosome 5. A map-based cloning approach was used to locate the axe1 mutations in an Arabidopsis RPD3-like histone deacetylase gene, referred to as HDA6. The axe1 mutant plants displayed increased expression of the GUS and HPH transgenes in the absence of auxin treatment and increased auxin-inducible expression of the transgenes compared with nonmutant control plants. None of a variety of endogenous, natural auxin-inducible genes in the mutant plants were upregulated like the transgenes, however. Results of treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine suggest that the axe1 mutations affect transgene silencing; however, histone deacetylase inhibitors had no affect on transgene silencing in mutant or control plants. The specific effect of AtHDA6 mutations on the auxin-responsive transgenes implicates this RPD3-like histone deacetylase as playing a role in transgene silencing. Furthermore, the effect of AtHDA6 on transgene silencing may be independent of its histone deacetylase activity.
authors.affiliation: Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA. murfettj@missouri.edu
authors.forename: J
authors.initials: J
authors.lastname: Murfett
authors.forename: X J
authors.initials: XJ
authors.lastname: Wang
authors.forename: G
authors.initials: G
authors.lastname: Hagen
authors.forename: T J
authors.initials: TJ
authors.lastname: Guilfoyle
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins; D019175:DNA Methylation; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017343:Genes, Plant; D017930:Genes, Reporter; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000235:genetics*; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D020218:Response Elements; D017386:Sequence Homology, Amino Acid; D019076:Transgenes
chemical_list: D029681:Arabidopsis Proteins; D056572:Histone Deacetylase Inhibitors; D007210:Indoleacetic Acids; D010940:Plant Proteins; C432452:AT5G63110 protein, Arabidopsis; D006655:Histone Deacetylases