title: Multiple functions of Kip-related protein5 connect endoreduplication and cell elongation.
abstract: Despite considerable progress in our knowledge regarding the cell cycle inhibitor of the Kip-related protein (KRP) family in plants, less is known about the coordination of endoreduplication and cell differentiation. In animals, the role of cyclin-dependent kinase (CDK) inhibitors as multifunctional factors coordinating cell cycle regulation and cell differentiation is well documented and involves not only the inhibition of CDK/cyclin complexes but also other mechanisms, among them the regulation of transcription. Interestingly, several plant KRPs have a punctuated distribution in the nucleus, suggesting that they are associated with heterochromatin. Here, one of these chromatin-bound KRPs, KRP5, has been studied in Arabidopsis (Arabidopsis thaliana). KRP5 is expressed in endoreduplicating cells, and loss of KRP5 function decreases endoreduplication, indicating that KRP5 is a positive regulator of endoreduplication. This regulation relies on several mechanisms: in addition to its role in cyclin/CDK kinase inhibition previously described, chromatin immunoprecipitation sequencing data combined with transcript quantification provide evidence that KRP5 regulates the transcription of genes involved in cell wall organization. Furthermore, KRP5 overexpression increases chromocenter decondensation and endoreduplication in the Arabidopsis trithorax-related protein5 (atxr5) atxr6 double mutant, which is deficient for the deposition of heterochromatin marks. Hence, KRP5 could bind chromatin to coordinately control endoreduplication and chromatin structure and allow the expression of genes required for cell elongation.
authors: Institut de Biologie des Plantes, Unité Mixte de Recherche 8618 Université Paris-Sud XI, 91405 Orsay, France.
authors: Teddy
authors: T
authors: Jégu
authors: David
authors: D
authors: Latrasse
authors: Marianne
authors: M
authors: Delarue
authors: Christelle
authors: C
authors: Mazubert
authors: Mickaël
authors: M
authors: Bourge
authors: Elodie
authors: E
authors: Hudik
authors: Sophie
authors: S
authors: Blanchet
authors: Marie-Noëlle
authors: MN
authors: Soler
authors: Céline
authors: C
authors: Charon
authors: Lieven
authors: L
authors: De Veylder
authors: Cécile
authors: C
authors: Raynaud
authors: Catherine
authors: C
authors: Bergounioux
authors: Moussa
authors: M
authors: Benhamed
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D050756:Cyclin-Dependent Kinase Inhibitor Proteins / Q000235:genetics / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism; D062951:Endoreduplication; D017343:Genes, Plant / Q000235:genetics; D006570:Heterochromatin / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D021381:Protein Transport; D036226:Seedlings / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C511744:CYCD3;1 protein, Arabidopsis; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D016213:Cyclins; D006570:Heterochromatin; C584094:KRP5 protein, Arabidopsis