title: Requirement for A-type cyclin-dependent kinase and cyclins for the terminal division in the stomatal lineage of Arabidopsis.
abstract: The Arabidopsis stoma is a specialized epidermal valve made up of a pair of guard cells around a pore whose aperture controls gas exchange between the shoot and atmosphere. Guard cells (GCs) are produced by a symmetric division of guard mother cells (GMCs). The R2R3-MYB transcription factor FOUR LIPS (FLP) and its paralogue MYB88 restrict the division of a GMC to one. Previously, the upstream regions of several core cell cycle genes were identified as the direct targets of FLP/MYB88, including the B-type cyclin-dependent kinase CDKB1;1 and A2-type cyclin CYCA2;3. Here we show that CDKA;1 is also an immediate direct target of FLP/MYB88 through the binding to cis-regulatory elements in the CDKA;1 promoter region. CDKA;1 activity is required not only for normal GMC divisions but also for the excessive cell overproliferation in flp myb88 mutant GMCs. The impaired defects of GMC division in cdkb1;1 1;2 mutants could be partially rescued by a stage-specific expression of CDKA;1. Although targeted overexpression of CDKA;1 does not affect stomatal development, ectopic expression of the D3-type cyclin CYCD3;2 induces GC subdivision, resulting in a stoma with 3-4 GCs instead of the normal two. Co-overexpression of CDKA;1 with CYCD3;2, but not with CYCA2;3, confers a synergistic effect with respect to GC subdivision. Thus, in addition to a role in stomatal formative asymmetric divisions at early developmental stages, CDKA;1 is needed in triggering GMC symmetric divisions at the late stage of stomatal development. However, timely down-regulation of CDKA;1-CYCD3 activity is required for restriction of GC proliferation.
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Kezhen
authors.initials: K
authors.lastname: Yang
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Hongzhe
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Xue
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Qu
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Zou
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China lejie@ibcas.ac.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Le
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D056743:Cyclin D3 / Q000235:genetics / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism*; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D054046:Plant Stomata / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C511744:CYCD3;1 protein, Arabidopsis; C000594291:CYCD3;2 protein, Arabidopsis; D056743:Cyclin D3; D016213:Cyclins; C434472:CDKA1 protein, Arabidopsis; D018844:Cyclin-Dependent Kinases
keywords: Arabidopsis; cell cycle; stomatal development; symmetric division; transcription factor.