title: Retinoblastoma related1 regulates asymmetric cell divisions in Arabidopsis.
abstract: Formative, also called asymmetric, cell divisions produce daughter cells with different identities. Like other divisions, formative divisions rely first of all on the cell cycle machinery with centrally acting cyclin-dependent kinases (CDKs) and their cyclin partners to control progression through the cell cycle. However, it is still largely obscure how developmental cues are translated at the cellular level to promote asymmetric divisions. Here, we show that formative divisions in the shoot and root of the flowering plant Arabidopsis thaliana are controlled by a common mechanism that relies on the activity level of the Cdk1 homolog CDKA;1, with medium levels being sufficient for symmetric divisions but high levels being required for formative divisions. We reveal that the function of CDKA;1 in asymmetric cell divisions operates through a transcriptional regulation system that is mediated by the Arabidopsis Retinoblastoma homolog RBR1. RBR1 regulates not only cell cycle genes, but also, independent of the cell cycle transcription factor E2F, genes required for formative divisions and cell fate acquisition, thus directly linking cell proliferation with differentiation. This mechanism allows the implementation of spatial information, in the form of high kinase activity, with intracellular gating of developmental decisions.
authors.affiliation: Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, IBMP, Unité propre de Recherche 2357, Université de Strasbourg, F-67084 Strasbourg cedex, France.
authors.forename: Annika K
authors.initials: AK
authors.lastname: Weimer
authors.forename: Moritz K
authors.initials: MK
authors.lastname: Nowack
authors.forename: Daniel
authors.initials: D
authors.lastname: Bouyer
authors.forename: Xin'Ai
authors.initials: X
authors.lastname: Zhao
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Harashima
authors.forename: Sadaf
authors.initials: S
authors.lastname: Naseer
authors.forename: Freya
authors.initials: F
authors.lastname: De Winter
authors.forename: Nico
authors.initials: N
authors.lastname: Dissmeyer
authors.forename: Niko
authors.initials: N
authors.lastname: Geldner
authors.forename: Arp
authors.initials: A
authors.lastname: Schnittger
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D060049:Asymmetric Cell Division / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D049109:Cell Proliferation; D018844:Cyclin-Dependent Kinases / Q000378:metabolism / Q000502:physiology; D050684:E2F Transcription Factors / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D018519:Meristem / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D054046:Plant Stomata / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D050684:E2F Transcription Factors; C487568:RBR1 protein, Arabidopsis; C434472:CDKA1 protein, Arabidopsis; D018844:Cyclin-Dependent Kinases