The Arabidopsis MCM2 gene is essential to embryo development and its over-expression alters root meristem function.
* Minichromosome maintenance (MCM) proteins are subunits of the pre-replication complex that probably function as DNA helicases during the S phase of the cell cycle. Here, we investigated the function of AtMCM2 in Arabidopsis. * To gain an insight into the function of AtMCM2, we combined loss- and gain-of-function approaches. To this end, we analysed two null alleles of AtMCM2, and generated transgenic plants expressing AtMCM2 downstream of the constitutive 35S promoter. * Disruption of AtMCM2 is lethal at a very early stage of embryogenesis, whereas its over-expression results in reduced growth and inhibition of endoreduplication. In addition, over-expression of AtMCM2 induces the formation of additional initials in the columella root cap. In the plt1,2 mutant, defective for root apical meristem maintenance, over-expression of AtMCM2 induces lateral root initiation close to the root tip, a phenotype not reported in the wild-type or in plt1,2 mutants, even when cell cycle regulators, such as AtCYCD3;1, were over-expressed. * Taken together, our results provide evidence for the involvement of AtMCM2 in DNA replication, and suggest that it plays a crucial role in root meristem function.
Ni
Di An
DA
Institut de Biotechnologie des Plantes (UMR8618), Université Paris-XI, 91405 Orsay, France.
Sozzani
Rosangela
R
Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy.
Blanchet
Sophie
S
Institut de Biotechnologie des Plantes (UMR8618), Université Paris-XI, 91405 Orsay, France.
Domenichini
Séverine
S
Institut de Biotechnologie des Plantes (UMR8618), Université Paris-XI, 91405 Orsay, France.
Reuzeau
Christophe
C
CropDesign N.V.-a BASF Plant Science Company, Technologiepark 3, B-9052 Gent, Belgium.
Cella
Rino
R
Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy.
Bergounioux
Catherine
C
Institut de Biotechnologie des Plantes (UMR8618), Université Paris-XI, 91405 Orsay, France.
Raynaud
Cécile
C
Institut de Biotechnologie des Plantes (UMR8618), Université Paris-XI, 91405 Orsay, France.
D017360:Arabidopsis / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics; D047108:Embryonic Development / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018519:Meristem / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D018517:Plant Roots / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic
D029681:Arabidopsis Proteins