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Jelle Van Leene,
Jens Hollunder,
Dominique Eeckhout,
Geert Persiau,
Eveline Van De Slijke,
Hilde Stals, Gert Van Isterdael,
Aurine Verkest,
Sandy Neirynck,
Yelle Buffel, [......],
Jim Beynon,
John C Larkin,
Yves Van de Peer,
Pierre Hilson,
Martin Kuiper,
Lieven De Veylder,
Harry Van Onckelen,
Dirk Inzé,
Erwin Witters,
Geert De Jaeger
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Jelle Van Leene,
Jens Hollunder,
Dominique Eeckhout,
Geert Persiau,
Eveline Van De Slijke,
Hilde Stals, Gert Van Isterdael,
Aurine Verkest,
Sandy Neirynck,
Yelle Buffel, [......],
Jim Beynon,
John C Larkin,
Yves Van de Peer,
Pierre Hilson,
Martin Kuiper,
Lieven De Veylder,
Harry Van Onckelen,
Dirk Inzé,
Erwin Witters,
Geert De Jaeger
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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.
The Plant Cell 04/2011; 23(4):1435-48. · 8.99 Impact Factor
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Steffen Vanneste,
Frederik Coppens,
Eunkyoung Lee,
Tyler J Donner,
Zidian Xie, Gert Van Isterdael,
Stijn Dhondt,
Freya De Winter,
Bert De Rybel,
Marnik Vuylsteke,
Lieven De Veylder,
Jiří Friml,
Dirk Inzé,
Erich Grotewold,
Enrico Scarpella,
Fred Sack,
Gerrit T S Beemster,
Tom Beeckman
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ABSTRACT: In multicellular organisms, morphogenesis relies on a strict coordination in time and space of cell proliferation and differentiation. In contrast to animals, plant development displays continuous organ formation and adaptive growth responses during their lifespan relying on a tight coordination of cell proliferation. How developmental signals interact with the plant cell-cycle machinery is largely unknown. Here, we characterize plant A2-type cyclins, a small gene family of mitotic cyclins, and show how they contribute to the fine-tuning of local proliferation during plant development. Moreover, the timely repression of CYCA2;3 expression in newly formed guard cells is shown to require the stomatal transcription factors FOUR LIPS/MYB124 and MYB88, providing a direct link between developmental programming and cell-cycle exit in plants. Thus, transcriptional downregulation of CYCA2s represents a critical mechanism to coordinate proliferation during plant development.
The EMBO Journal 01/2011; 30(16):3430-41. · 9.20 Impact Factor
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ABSTRACT: Defining protein complexes is critical to virtually all aspects of cell biology because most cellular processes are regulated by stable or more dynamic protein interactions. Elucidation of the protein-protein interaction network around transcription factors is essential to fully understand their function and regulation. In the last decade, new technologies have emerged to study protein-protein interactions under near-physiological conditions. We have developed a high-throughput tandem affinity purification (TAP)/mass spectrometry (MS) platform for cell suspension cultures to analyze protein complexes in Arabidopsis thaliana. This streamlined platform follows an integrated approach comprising generic Gateway-based vectors with high cloning flexibility, the fast generation of transgenic suspension cultures, TAP adapted for plant cells, and tandem matrix-assisted laser desorption ionization MS for the identification of purified proteins. Recently, we evaluated the GS tag, originally developed to study mammalian protein complexes, that combines two IgG-binding domains of protein G with a streptavidin-binding peptide, separated by two tobacco etch virus cleavage sites. We found that this GS tag outperforms the traditional TAP tag in plant cells, regarding both specificity and complex yield. Here, we provide detailed protocols of the GS-based TAP platform that allowed us to characterize transcription factor complexes involved in signaling in response to the plant phytohormone jasmonate.
Methods in molecular biology (Clifton, N.J.) 01/2011; 754:195-218.
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ABSTRACT: A significant increase in shoot biomass and seed yield has always been the dream of plant biologists who wish to dedicate their fundamental research to the benefit of mankind; the first green revolution about half a century ago represented a crucial step towards contemporary agriculture and the development of high-yield varieties of cereal grains. Although there has been a steady rise in our food production from then onwards, the currently applied technology and the available crop plants will not be sufficient to feed the rapidly growing world population. In this opinion article, we highlight several below-ground characteristics of plants such as root architecture, nutrient uptake and nitrogen fixation as promising features enabling a very much needed new green revolution.
Trends in Plant Science 11/2010; 15(11):600-7. · 11.05 Impact Factor
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Bert De Rybel,
Valya Vassileva,
Boris Parizot,
Marlies Demeulenaere,
Wim Grunewald,
Dominique Audenaert,
Jelle Van Campenhout,
Paul Overvoorde,
Leentje Jansen,
Steffen Vanneste, [......],
Tara Holman, Gert Van Isterdael,
Géraldine Brunoud,
Marnik Vuylsteke,
Teva Vernoux,
Lieven De Veylder,
Dirk Inzé,
Dolf Weijers,
Malcolm J Bennett,
Tom Beeckman
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ABSTRACT: Lateral roots are formed at regular intervals along the main root by recurrent specification of founder cells. To date, the mechanism by which branching of the root system is controlled and founder cells become specified remains unknown.
Our study reports the identification of the auxin regulatory components and their target gene, GATA23, which control lateral root founder cell specification. Initially, a meta-analysis of lateral root-related transcriptomic data identified the GATA23 transcription factor. GATA23 is expressed specifically in xylem pole pericycle cells before the first asymmetric division and is correlated with oscillating auxin signaling maxima in the basal meristem. Also, functional studies revealed that GATA23 controls lateral root founder cell identity. Finally, we show that an Aux/IAA28-dependent auxin signaling mechanism in the basal meristem controls GATA23 expression.
We have identified the first molecular components that control lateral root founder cell identity in the Arabidopsis root. These include an IAA28-dependent auxin signaling module in the basal meristem region that regulates GATA23 expression and thereby lateral root founder cell specification and root branching patterns.
Current biology: CB 09/2010; 20(19):1697-706. · 10.99 Impact Factor
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Jelle Van Leene,
Jens Hollunder,
Dominique Eeckhout,
Geert Persiau,
Eveline Van De Slijke,
Hilde Stals, Gert Van Isterdael,
Aurine Verkest,
Sandy Neirynck,
Yelle Buffel, [......],
Jim Beynon,
John C Larkin,
Yves Van de Peer,
Pierre Hilson,
Martin Kuiper,
Lieven De Veylder,
Harry Van Onckelen,
Dirk Inzé,
Erwin Witters,
Geert De Jaeger
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ABSTRACT: Cell proliferation is the main driving force for plant growth. Although genome sequence analysis revealed a high number of cell cycle genes in plants, little is known about the molecular complexes steering cell division. In a targeted proteomics approach, we mapped the core complex machinery at the heart of the Arabidopsis thaliana cell cycle control. Besides a central regulatory network of core complexes, we distinguished a peripheral network that links the core machinery to up- and downstream pathways. Over 100 new candidate cell cycle proteins were predicted and an in-depth biological interpretation demonstrated the hypothesis-generating power of the interaction data. The data set provided a comprehensive view on heterodimeric cyclin-dependent kinase (CDK)-cyclin complexes in plants. For the first time, inhibitory proteins of plant-specific B-type CDKs were discovered and the anaphase-promoting complex was characterized and extended. Important conclusions were that mitotic A- and B-type cyclins form complexes with the plant-specific B-type CDKs and not with CDKA;1, and that D-type cyclins and S-phase-specific A-type cyclins seem to be associated exclusively with CDKA;1. Furthermore, we could show that plants have evolved a combinatorial toolkit consisting of at least 92 different CDK-cyclin complex variants, which strongly underscores the functional diversification among the large family of cyclins and reflects the pivotal role of cell cycle regulation in the developmental plasticity of plants.
Molecular Systems Biology 08/2010; 6:397. · 8.63 Impact Factor
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ABSTRACT: The plant rhizosphere harbors many different microorganisms, ranging from plant growth-promoting bacteria to devastating plant parasites. Some of these microbes are able to induce de novo organ formation in infected roots. Certain soil bacteria, collectively called rhizobia, form a symbiotic interaction with legumes, leading to the formation of nitrogen-fixing root nodules. Sedentary endoparasitic nematodes, on the other hand, induce highly specialized feeding sites in infected plant roots from which they withdraw nutrients. In order to establish these new root structures, it is thought that these organisms use and manipulate the endogenous molecular and physiological pathways of their hosts. Over the years, evidence has accumulated reliably demonstrating the involvement of the plant hormone auxin. Moreover, the auxin responses during microbe-induced de novo organ formation seem to be dynamic, suggesting that plant-associated microbes can actively modify their host's auxin transport. In this review, we focus on recent findings in auxin transport mechanisms during plant development and on how plant symbionts and parasites have evolved to manipulate these mechanisms for their own purposes.
The Plant Cell 09/2009; 21(9):2553-62. · 8.99 Impact Factor
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Véronique Boudolf,
Tim Lammens,
Joanna Boruc,
Jelle Van Leene,
Hilde Van Den Daele,
Sara Maes, Gert Van Isterdael,
Eugenia Russinova,
Eva Kondorosi,
Erwin Witters,
Geert De Jaeger,
Dirk Inzé,
Lieven De Veylder
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ABSTRACT: The mitosis-to-endocycle transition requires the controlled inactivation of M phase-associated cyclin-dependent kinase (CDK) activity. Previously, the B-type CDKB1;1 was identified as an important negative regulator of endocycle onset. Here, we demonstrate that CDKB1;1 copurifies and associates with the A2-type cyclin CYCA2;3. Coexpression of CYCA2;3 with CDKB1;1 triggered ectopic cell divisions and inhibited endoreduplication. Moreover, the enhanced endoreduplication phenotype observed after overexpression of a dominant-negative allele of CDKB1;1 could be partially complemented by CYCA2;3 co-overexpression, illustrating that both subunits unite in vivo to form a functional complex. CYCA2;3 protein stability was found to be controlled by CCS52A1, an activator of the anaphase-promoting complex. We conclude that CCS52A1 participates in endocycle onset by down-regulating CDKB1;1 activity through the destruction of CYCA2;3.
Plant physiology 06/2009; 150(3):1482-93. · 6.53 Impact Factor
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Tom Beeckman,
Dominique Audenaert,
Giel Van Noorden,
Boris Parizot,
Bert De Rybel,
Wim Grunewald,
Leentje Jansen,
Lorena Lopez Galvis,
Mirande Naudts,
Charlotte Vanquickenborne,
Long Nguyen, Gert Van Isterdael
Micro, macro, mega: collectie Ocsinberg, keerpunt in de geschiedenis van de microscopie. 05/2009; 3:75-77.
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Ive De Smet,
Valya Vassileva,
Bert De Rybel,
Mitchell P Levesque,
Wim Grunewald,
Daniël Van Damme,
Giel Van Noorden,
Mirande Naudts, Gert Van Isterdael,
Rebecca De Clercq,
Jean Y Wang,
Nicholas Meuli,
Steffen Vanneste,
Jirí Friml,
Pierre Hilson,
Gerd Jürgens,
Gwyneth C Ingram,
Dirk Inzé,
Philip N Benfey,
Tom Beeckman
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ABSTRACT: During the development of multicellular organisms, organogenesis and pattern formation depend on formative divisions to specify and maintain pools of stem cells. In higher plants, these activities are essential to shape the final root architecture because the functioning of root apical meristems and the de novo formation of lateral roots entirely rely on it. We used transcript profiling on sorted pericycle cells undergoing lateral root initiation to identify the receptor-like kinase ACR4 of Arabidopsis as a key factor both in promoting formative cell divisions in the pericycle and in constraining the number of these divisions once organogenesis has been started. In the root tip meristem, ACR4 shows a similar action by controlling cell proliferation activity in the columella cell lineage. Thus, ACR4 function reveals a common mechanism of formative cell division control in the main root tip meristem and during lateral root initiation.
Science 11/2008; 322(5901):594-7. · 31.20 Impact Factor
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Jelle Van Leene,
Hilde Stals,
Dominique Eeckhout,
Geert Persiau,
Eveline Van De Slijke, Gert Van Isterdael,
Annelies De Clercq,
Eric Bonnet,
Kris Laukens,
Noor Remmerie,
Kim Henderickx,
Thomas De Vijlder,
Azmi Abdelkrim,
Anne Pharazyn,
Harry Van Onckelen,
Dirk Inzé,
Erwin Witters,
Geert De Jaeger
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ABSTRACT: Defining protein complexes is critical to virtually all aspects of cell biology because many cellular processes are regulated by stable protein complexes, and their identification often provides insights into their function. We describe the development and application of a high throughput tandem affinity purification/mass spectrometry platform for cell suspension cultures to analyze cell cycle-related protein complexes in Arabidopsis thaliana. Elucidation of this protein-protein interaction network is essential to fully understand the functional differences between the highly redundant cyclin-dependent kinase/cyclin modules, which are generally accepted to play a central role in cell cycle control, in all eukaryotes. Cell suspension cultures were chosen because they provide an unlimited supply of protein extracts of actively dividing and undifferentiated cells, which is crucial for a systematic study of the cell cycle interactome in the absence of plant development. Here we report the mapping of a protein interaction network around six known core cell cycle proteins by an integrated approach comprising generic Gateway-based vectors with high cloning flexibility, the fast generation of transgenic suspension cultures, tandem affinity purification adapted for plant cells, matrix-assisted laser desorption ionization tandem mass spectrometry, data analysis, and functional assays. We identified 28 new molecular associations and confirmed 14 previously described interactions. This systemic approach provides new insights into the basic cell cycle control mechanisms and is generally applicable to other pathways in plants.
Molecular & Cellular Proteomics 07/2007; 6(7):1226-38. · 7.40 Impact Factor
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Steffen Vanneste,
Bert De Rybel,
Gerrit T S Beemster,
Karin Ljung,
Ive De Smet, Gert Van Isterdael,
Mirande Naudts,
Ryusuke Iida,
Wilhelm Gruissem,
Masao Tasaka,
Dirk Inzé,
Hidehiro Fukaki,
Tom Beeckman
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ABSTRACT: To study the mechanisms behind auxin-induced cell division, lateral root initiation was used as a model system. By means of microarray analysis, genome-wide transcriptional changes were monitored during the early steps of lateral root initiation. Inclusion of the dominant auxin signaling mutant solitary root1 (slr1) identified genes involved in lateral root initiation that act downstream of the auxin/indole-3-acetic acid (AUX/IAA) signaling pathway. Interestingly, key components of the cell cycle machinery were strongly defective in slr1, suggesting a direct link between AUX/IAA signaling and core cell cycle regulation. However, induction of the cell cycle in the mutant background by overexpression of the D-type cyclin (CYCD3;1) was able to trigger complete rounds of cell division in the pericycle that did not result in lateral root formation. Therefore, lateral root initiation can only take place when cell cycle activation is accompanied by cell fate respecification of pericycle cells. The microarray data also yielded evidence for the existence of both negative and positive feedback mechanisms that regulate auxin homeostasis and signal transduction in the pericycle, thereby fine-tuning the process of lateral root initiation.
The Plant Cell 12/2005; 17(11):3035-50. · 8.99 Impact Factor
