title: TOPLESS regulates apical embryonic fate in Arabidopsis.
abstract: The embryos of seed plants develop with an apical shoot pole and a basal root pole. In Arabidopsis, the topless-1 (tpl-1) mutation transforms the shoot pole into a second root pole. Here, we show that TPL resembles known transcriptional corepressors and that tpl-1 acts as a dominant negative mutation for multiple TPL-related proteins. Mutations in the putative coactivator HISTONE ACETYLTRANSFERASE GNAT SUPERFAMILY1 suppress the tpl-1 phenotype. Mutations in HISTONE DEACETYLASE19, a putative corepressor, increase the penetrance of tpl-1 and display similar apical defects. These data point to a transcriptional repression mechanism that prevents root formation in the shoot pole during Arabidopsis embryogenesis.
authors.affiliation: Plant Biology Laboratory, Salk Institute for Biological Sciences, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. long@salk.edu
authors.forename: Jeff A
authors.initials: JA
authors.lastname: Long
authors.forename: Carolyn
authors.initials: C
authors.lastname: Ohno
authors.forename: Zachery R
authors.initials: ZR
authors.lastname: Smith
authors.forename: Elliot M
authors.initials: EM
authors.lastname: Meyerowitz
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D016764:Cell Polarity; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D018506:Gene Expression Regulation, Plant; D006655:Histone Deacetylases / Q000235:genetics / Q000502:physiology; D009154:Mutation; D018517:Plant Roots / Q000196:embryology; D018520:Plant Shoots / Q000196:embryology; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D012639:Seeds
chemical_list: D029681:Arabidopsis Proteins; D006655:Histone Deacetylases; D012097:Repressor Proteins; C511291:At1g15750 protein, Arabidopsis; C507152:HDA19 protein, Arabidopsis