title: Arabidopsis guard cell integrity involves the epigenetic stabilization of the FLP and FAMA transcription factor genes.
abstract: Arabidopsis guard cell (GC) fate is conferred via a transient pulse of expression of FAMA that encodes a bHLH transcription factor. Stomata often function for years, suggesting that the FAMA expression window stabilizes long-term GC identity or that additional factors operate. Transgenic lines harboring a copy of a FAMA transgene were found to induce the fate resetting of mature GCs to that of lineage-specific stem cells causing new stomata to arise within shells of the old, a Stoma-in-Stoma (SIS) phenotype. These lines disrupt the normal trimethylation on lysine 27 of histone3 (H3K27me3) on stomatal stem cell genes, a phenotype rescued by constitutive expression of the Polycomb Group (PcG) gene CURLY LEAF. Thus the stability of stomatal fate is enforced by a PcG-mediated reduction in the transcriptional accessibility of stem cell genes and by the endogenous FAMA gene itself. Moreover, a transgenic FOUR LIPS gene, which encodes a MYB protein that is not required for GC fate, also induces a SIS phenotype and disrupts H3K27 trimethylation. Thus FLP might indirectly enforce GC fate as well.
authors.affiliation: Department of Botany, University of British Columbia, Vancouver, V6T 1Z4, Canada.
authors.forename: Eunkyoung
authors.initials: E
authors.lastname: Lee
authors.forename: Jessica Regan
authors.initials: JR
authors.lastname: Lucas
authors.forename: Justin
authors.initials: J
authors.lastname: Goodrich
authors.forename: Fred David
authors.initials: FD
authors.lastname: Sack
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D019070:Cell Lineage / Q000235:genetics; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D008745:Methylation; D018613:Microscopy, Confocal; D010641:Phenotype; D054046:Plant Stomata / Q000166:cytology / Q000378:metabolism*; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D049452:Green Fluorescent Proteins; D006657:Histones; D018398:Homeodomain Proteins; D008239:Lysine; D014157:Transcription Factors; C104597:CURLY LEAF protein, Arabidopsis; C517481:FAMA protein, Arabidopsis; C507998:FLP protein, Arabidopsis; C517479:MUTE protein, Arabidopsis; C517480:SPEECHLESS protein, Arabidopsis
keywords: Arabidopsis; FAMA; FOUR LIPS; cell fate; guard cell; stomatal development