SGAP : Cytosketon dynamics

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JP Bourgin

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Organisation & dynamics of the cytoskeleton in Arabidopsis thaliana

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Keywords : Arabidopsis thaliana - cytoskeleton - development - mutant - microtubule - preprophase band

Doctoral school affiliation : ED145 "Sciences du Végétal" Université Paris 11-Orsay

Contacts :

Génétique et Amélioration des Plantes
INRA - Centre de Versailles Grignon
Route de Saint-Cyr 78026 Versailles Cedex
fax +33 (0)1 30 83 33 19

David Bouchez
Group leader

tel +33 (0)1 30 83 33 94
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Magali Goussot
Technician

tel +33 (0)1 30 83 33 94
mail :

Yann Duroc
Post-doc

tel +33 (0)1 30 83 33 94
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	Martine Pastuglia Senior scientist tel +33 (0)1 30 83 33 94 mail :
	Katia Belcram Technician tel +33 (0)1 30 83 33 04 mail :
	Evelyne Duvernois (CDD) tel 01 30 83 33 94

Background :

In higher plants, the cytoskeleton steadily undergoes structural reorganizations which accompany and/or determine every stage in cell division, elongation and differentiation (the microtubules during cell division live). We have isolated mutants affected in essential components of the cortical cytoskeleton, which uncouple cell division and elongation from morphogenesis and organ formation. These mutants allow to address several fundamental questions in plant cell biology, like the role of specific structures of the plant cortical cytoskeleton in cell division and elongation (like the preprophase band of microtubules, or PPB), and more generally the importance of these cellular events in morphogenesis and organogenesis in plants. > Further details <

Our aim is to better characterize the molecular components involved in the dynamics of the cytoskeleton in Arabidopsis thaliana, to study the regulation pathways and molecular interactions involved in this complex process, and to understand the role of these cellular phenomenons in plant morphogenesis and evolution.

Main Results :

We have isolated a new class of Arabidopsis mutants named "tonneau" and "fass", which have strong morphological alterations. We have noted severe defects in cell division and elongation in mutant cells. These cells do not position their division plane properly and are unable of polarised cell expansion.

Everything about the ton mutants here.

< photo : on the left, a wild-type plantlet 7 days after germination ; on the right a ton mutant plantlet at the same age.

The defect can be traced to the cortical cytoskeleton, which appears disorganised in mutant cells. These cells never form a preprophase band of microtubules (PPB), a structure that precisely marks the position of the future division plane during the early phases of mitosis.

What the hell is a PPB ? response here

< photo : arrows point to the preprophase band of microtubules (PPB), here as a section, around the nucleus which appears devoid of microtubules and unmarked by the fluorescent marker used : a fusion between MAP4 microtubule binding domain and the green fluorescent protein.

These mutants have the spectacular ability to uncouple cellular processes (division & elongation) from morphogenesis : mutant plants are still able to form meristems and organs and to differentiate cells. The genes and proteins affected by these mutations have been isolated and current studies aim at better understanding the biochemical and cellular bases of their function > further details<.

Selected Publications :

Azimzadeh J, Nacry P, Christodoulidou A, Drevensek S, Camilleri C, Amiour N, Parcy F, Pastuglia M and Bouchez D (2008). Arabidopsis TONNEAU1 proteins are essential for preprophase band formation, share similarity with human centrosomal proteins and interact with centrin. Plant Cell, 20: 2146–2159 (pubmed)

Pastuglia M, Bouchez D (2007). Molecular encounters at microtubule ends in the plant cell cortex. Curr Op Plant Biol 10:1-7 (pubmed)

Pierre M, Traverso JA, Boisson B, Domenichini S, Bouchez D, Giglione C, Meinnel T (2007). N-myristoylation regulates the SnRK1 pathway in Arabidopsis. Plant Cell 19 :2804-2812 (pubmed)

Pastuglia M, Azimzadeh J, Goussot M, Camilleri C, Belcram K, Evrard JL, Schmit AC, Guerche P and Bouchez D (2006). Gamma-tubulin is essential for microtubule organization and development in Arabidopsis. Plant Cell 18 : 1412-1425 (pubmed)

Ostrowski MF, David J, Santoni S, McKhann H, Reboud X, Le Corre V, Camilleri C, Brunel D, Bouchez D, Faure B, Bataillon T (2006) Evidence for a large-scale population structure among accessions of Arabidopsis thaliana: possible causes and consequences for the distribution of linkage disequilibrium. Mol Ecol 15 :1507-1517 (pubmed)

Camilleri C, Azimzadeh J, Pastuglia M, Bellini C, Grandjean O and Bouchez D (2002). The Arabidopsis TONNEAU2 gene encodes a putative novel PP2A regulatory subunit essential for the control of cortical cytoskeleton. Plant Cell, 14 : 833-845. (pubmed)

Azimzadeh J, Traas J, Pastuglia M. (2001) Molecular aspects of microtubule dynamics in plants. Curr Opin Plant Biol. 4, 513-519. (pubmed)

Nacry P, Camilleri C, Courtial B, Caboche M, Bouchez D (1998) Major chromosomal rearrangements induced by T-DNA transformation in Arabidopsis. Genetics 149 : 641-650. (pubmed)

Thion L, Mazars C, Nacry P, Bouchez D, Moreau M, Ranjeva R, Thuleau P (1998). Plasma membrane depolarization-activated calcium channels, stimulated by microtubule-depolymerizing drugs in wild-type Arabidopsis thaliana protoplasts, display constitutively large activities and a longer half-life in ton2 mutant cells affected in the organizationof cortical microtubules. Plant Journal 13 : 603-610. (pubmed)

Traas J, Bellini C, Nacry P, Kronenberger J, Bouchez D, Caboche M (1995). Normal differentiation patterns in plants lacking microtubular preprophase bands. Nature 375 : 676-677.

Book chapters :
Johnson X, Bouchez D (2007) The model species, Arabidopsis thaliana. In : Functional Plant Genomics. JF Morot-Gaudry, P Lea, JF Briat, Eds. Science Publishers, Enfield, NH, USA. pp 385-396
Granier F and Bouchez D (2007). Mutant Libraries: a High-throughput Arabidopsis Reverse Genetics System. In : Functional Plant Genomics. JF Morot-Gaudry, P Lea, JF Briat, Eds. Science Publishers, Enfield, NH, USA. pp 143-164

> Publication list and selected links on the cytoskeleton
> Informations and resources