title: The Arabidopsis thaliana checkpoint kinase WEE1 protects against premature vascular differentiation during replication stress.
abstract: A sessile lifestyle forces plants to respond promptly to factors that affect their genomic integrity. Therefore, plants have developed checkpoint mechanisms to arrest cell cycle progression upon the occurrence of DNA stress, allowing the DNA to be repaired before onset of division. Previously, the WEE1 kinase had been demonstrated to be essential for delaying progression through the cell cycle in the presence of replication-inhibitory drugs, such as hydroxyurea. To understand the severe growth arrest of WEE1-deficient plants treated with hydroxyurea, a transcriptomics analysis was performed, indicating prolonged S-phase duration. A role for WEE1 during S phase was substantiated by its specific accumulation in replicating nuclei that suffered from DNA stress. Besides an extended replication phase, WEE1 knockout plants accumulated dead cells that were associated with premature vascular differentiation. Correspondingly, plants without functional WEE1 ectopically expressed the vascular differentiation marker VND7, and their vascular development was aberrant. We conclude that the growth arrest of WEE1-deficient plants is due to an extended cell cycle duration in combination with a premature onset of vascular cell differentiation. The latter implies that the plant WEE1 kinase acquired an indirect developmental function that is important for meristem maintenance upon replication stress.
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium.
authors.forename: Toon
authors.initials: T
authors.lastname: Cools
authors.forename: Anelia
authors.initials: A
authors.lastname: Iantcheva
authors.forename: Annika K
authors.initials: AK
authors.lastname: Weimer
authors.forename: Shannah
authors.initials: S
authors.lastname: Boens
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Sara
authors.initials: S
authors.lastname: Maes
authors.forename: Hilde
authors.initials: H
authors.lastname: Van den Daele
authors.forename: Gert
authors.initials: G
authors.lastname: Van Isterdael
authors.forename: Arp
authors.initials: A
authors.lastname: Schnittger
authors.forename: Lieven
authors.initials: L
authors.lastname: De Veylder
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001761:Bleomycin / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D016000:Cluster Analysis; D004260:DNA Repair / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D004795:Enzyme Stability / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D006918:Hydroxyurea / Q000494:pharmacology; D007700:Kinetics; D018519:Meristem / Q000166:cytology / Q000187:drug effects; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D058526:Plant Vascular Bundle / Q000166:cytology* / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D016196:S Phase / Q000187:drug effects; D013312:Stress, Physiological / Q000187:drug effects; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; D001761:Bleomycin; D017346:Protein Serine-Threonine Kinases; C514674:WEE1 protein, Arabidopsis; D006918:Hydroxyurea