title: A protodermal miR394 signal defines a region of stem cell competence in the Arabidopsis shoot meristem.
abstract: A long-standing question in plants and animals is how spatial patterns are maintained within stem cell niches despite ongoing cell divisions. Here we address how, during shoot meristem formation in Arabidopsis thaliana, the three apical cell layers acquire stem cell identity. Using a sensitized mutant screen, we identified miR394 as a mobile signal produced by the surface cell layer (the protoderm) that confers stem cell competence to the distal meristem by repressing the F box protein LEAF CURLING RESPONSIVENESS. This repression is required to potentiate signaling from underneath the stem cells by the transcription factor WUSCHEL, maintaining stem cell pluripotency. The interaction of two opposing signaling centers provides a mechanistic framework of how stem cells are localized at the tip of the meristem. Although the constituent cells change, the surface layer provides a stable point of reference in the self-organizing meristem.
authors: BIOSS Centre for Biological Signalling Studies, Faculty of Biology, Albert-Ludwigs-University Freiburg, Schaenzlestrasse 1, 79104 Freiburg, Germany.
authors: Steffen
authors: S
authors: Knauer
authors: Anna L
authors: AL
authors: Holt
authors: Ignacio
authors: I
authors: Rubio-Somoza
authors: Elise J
authors: EJ
authors: Tucker
authors: Annika
authors: A
authors: Hinze
authors: Melanie
authors: M
authors: Pisch
authors: Marie
authors: M
authors: Javelle
authors: Marja C
authors: MC
authors: Timmermans
authors: Matthew R
authors: MR
authors: Tucker
authors: Thomas
authors: T
authors: Laux
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000378:metabolism*; D018519:Meristem / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D039904:Pluripotent Stem Cells / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D018398:Homeodomain Proteins; C579342:MIRN394 microRNA, Arabidopsis; D035683:MicroRNAs; C116421:WUSCHEL protein, Arabidopsis