title: SAMBA, a plant-specific anaphase-promoting complex/cyclosome regulator is involved in early development and A-type cyclin stabilization.
abstract: The anaphase-promoting complex/cyclosome (APC/C) is a large multiprotein E3 ubiquitin ligase involved in ubiquitin-dependent proteolysis of key cell cycle regulatory proteins, including the destruction of mitotic cyclins at the metaphase-to-anaphase transition. Despite its importance, the role of the APC/C in plant cells and the regulation of its activity during cell division remain poorly understood. Here, we describe the identification of a plant-specific negative regulator of the APC/C complex, designated SAMBA. In Arabidopsis thaliana, SAMBA is expressed during embryogenesis and early plant development and plays a key role in organ size control. Samba mutants produced larger seeds, leaves, and roots, which resulted from enlarged root and shoot apical meristems, and, additionally, they had a reduced fertility attributable to a hampered male gametogenesis. Inactivation of SAMBA stabilized A2-type cyclins during early development. Our data suggest that SAMBA regulates cell proliferation during early development by targeting CYCLIN A2 for APC/C-mediated proteolysis.
authors.affiliation: Department of Plant Systems Biology, VIB, Ghent University, 9052 Ghent, Belgium.
authors.forename: Nubia B
authors.initials: NB
authors.lastname: Eloy
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gonzalez
authors.forename: Jelle
authors.initials: J
authors.lastname: Van Leene
authors.forename: Katrien
authors.initials: K
authors.lastname: Maleux
authors.forename: Hannes
authors.initials: H
authors.lastname: Vanhaeren
authors.forename: Liesbeth
authors.initials: L
authors.lastname: De Milde
authors.forename: Stijn
authors.initials: S
authors.lastname: Dhondt
authors.forename: Leen
authors.initials: L
authors.lastname: Vercruysse
authors.forename: Erwin
authors.initials: E
authors.lastname: Witters
authors.forename: Raphaël
authors.initials: R
authors.lastname: Mercier
authors.forename: Laurence
authors.initials: L
authors.lastname: Cromer
authors.forename: Gerrit T S
authors.initials: GT
authors.lastname: Beemster
authors.forename: Han
authors.initials: H
authors.lastname: Remaut
authors.forename: Marc C E
authors.initials: MC
authors.lastname: Van Montagu
authors.forename: Geert
authors.initials: G
authors.lastname: De Jaeger
authors.forename: Paulo C G
authors.initials: PC
authors.lastname: Ferreira
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
mesh_terms: D000595:Amino Acid Sequence; D064173:Anaphase-Promoting Complex-Cyclosome; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D002453:Cell Cycle; D019925:Cyclin A / Q000737:chemistry*; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D011058:Pollen / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics / Q000502:physiology*
chemical_list: D019925:Cyclin A; D010940:Plant Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome