title: High-resolution boundary analysis during Arabidopsis thaliana flower development.
abstract: We report a comparative analysis of cell proliferation patterns during Arabidopsis flower development. Cell division was evaluated by a direct method, i.e. the 5-bromo-2'-deoxyuridine (BrdU) incorporation/immunodetection procedure. BrdU patterns in wild-type plants were correlated with the expression profiles of both several cell cycle genes involved in the control of the G(1)/S transition and cell cycle-related repressor genes, MSI4 and MSI5, encoding WD-repeat proteins. To evaluate how proliferation patterns arise with respect to boundaries and vice versa, the expression of a boundary gene, CUP SHAPED COTYLEDON (CUC)2, was determined. Combining these approaches, we demonstrate that boundaries between inflorescence and floral meristems and between floral whorls are narrow bands of non-dividing cells. In addition, we show that negative and positive regulators of cell proliferation are simultaneously and continuously expressed in dividing meristematic domains, being excluded from boundary cells. Finally, BrdU incorporation and CUC2 in situ hybridisation patterns were analysed in two mutant backgrounds, agamous (ag)-1 and superman (sup)-1, in order to assess changes in boundary establishment and different levels of indeterminacy under conditions of altered proliferation at the floral meristem centre.
authors.affiliation: Laboratoire Reproduction et Développement des Plantes, UMR 5667, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Breuil-Broyer
authors.forename: Patrice
authors.initials: P
authors.lastname: Morel
authors.forename: Janice
authors.initials: J
authors.lastname: de Almeida-Engler
authors.forename: Vincent
authors.initials: V
authors.lastname: Coustham
authors.forename: Ioan
authors.initials: I
authors.lastname: Negrutiu
authors.forename: Christophe
authors.initials: C
authors.lastname: Trehin
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics; D001973:Bromodeoxyuridine / Q000378:metabolism; D002453:Cell Cycle; D002455:Cell Division; D035264:Flowers / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018519:Meristem / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D009154:Mutation
chemical_list: D029681:Arabidopsis Proteins; C107294:CUC2 protein, Arabidopsis; D001973:Bromodeoxyuridine