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.

Gene Duplicability of Core Genes Is Highly Consistent across All Angiosperms

“…A compendium of protein-protein interactions in Arabidopsis was constructed combining the following sources: BioGRID 3.2.110 (ChatrAryamontri et al, 2013), CORNET (only experimentally validated interactions) (De Bodt et al, 2012), STRINGv9.1 (only category Binding) (Franceschini et al, 2013), EVEX (only category binding) (Van Landeghem et al, 2013), and a TAP data set assembled from literature (Takahashi et al, 2008;Pauwels et al, 2010;Van Leene et al, 2010;Bassard et al, 2012;Domenichini et al, 2012;Eloy et al, 2012;Antoni et al, 2013;Cromer et al, 2013;Di Rubbo et al, 2013;Heijde et al, 2013;Spinner et al, 2013;Fonseca et al, 2014;Gadeyne et al, 2014;Perez et al, 2014;Vercruyssen et al, 2014). After removing redundancy and self-interactions, this lead to a set with a total of 46,113 interactions between 9813 proteins.…”

A Journey Through a Leaf: Phenomics Analysis of Leaf Growth inArabidopsis thaliana

“…For example, downregulation of SAMBA (AT1G32310) enhances the volume of leaf primordia in early stages of development (Eloy et al, 2012) and overexpression of AN3 enhances both the rate of cell division and the duration of the cell division phase (Horiguchi et al, 2005;Lee et al, 2009). Similarly, overexpression of the brassinosteroid receptor, BRASSINOSTEROID INSENSITIVE 1 (BRI1; AT4G39400), the transcription factor GRF5 or the mi-RNA, JAGGED AND WAVY (JAW; AT4G23713), Palatnik et al, 2003;Horiguchi et al, 2005) increases leaf cell number by extending the duration of cell division, resulting in an increased leaf area.…”

Forever Young: The Role of Ubiquitin Receptor DA1 and E3 Ligase BIG BROTHER in Controlling Leaf Growth and Development

“…Later, cells stop dividing at the tip of the leaf, and a cell cycle arrest front proceeds in a basipetal direction (Andriankaja et al, 2012;Donnelly et al, 1999;Kazama et al, 2010). Down-regulation of the SAMBA gene has been shown to result in larger leaf primordia during the earliest stages of development (Eloy et al, 2012). The duration of the cell proliferation phase is extended in plants overexpressing AINTEGUMENTA (ANT), ANGUSTIFOLIA3 (AN3), GROWTH REGULATING FACTOR3 (GRF3), GRF5, and miR319 (also known as JAGGED AND WAVY [JAW]; Debernardi et al, 2014;Gonzalez et al, 2010;Horiguchi et al, 2005;Mizukami and Fischer, 2000;Palatnik et al, 2003;Vercruyssen et al, 2015), leading to the formation of larger leaves.…”