Arabidopsis ULTRAVIOLET-B-INSENSITIVE4 Maintains Cell Division Activity by Temporal Inhibition of the Anaphase-Promoting Complex/Cyclosome

• Published in: The Plant cell 2011-12, Vol.23 (12), p.4394-4410
• Main Authors: Heyman, Jefri, Van den Daele, Hilde, De Wit, Kevin, Boudolf, Véronique, Berckmans, Barbara, Verkest, Aurine, Kamel, Claire Lessa Alvim, De Jaeger, Geert, Koncz, Csaba, De Veylder, Lieven
• Format: Article
• Language: English
• Subjects: Anaphase-promoting complex; Anaphase-Promoting Complex-Cyclosome; Arabidopsis; Arabidopsis - anatomy & histology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell cycle; Cell cycle proteins; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Differentiation; Cell Division; Chromatin Immunoprecipitation; Cyclin A2 - genetics; Cyclin A2 - metabolism; Cyclin-Dependent Kinases - genetics; Cyclin-Dependent Kinases - metabolism; Cyclins; DNA; DNA biosynthesis; E2F protein; E2F Transcription Factors - genetics; E2F Transcription Factors - metabolism; Epidermal cells; Gene expression regulation; Gene Expression Regulation, Plant; Genetic Complementation Test; Growth rate; Inactivation; Meristem - growth & development; Meristem - metabolism; Meristem - ultrastructure; Meristems; Microscopy, Electron, Scanning; Mitosis; Mutagenesis, Site-Directed; Plant cells; Plant growth; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - metabolism; Plants; Protein Interaction Domains and Motifs; Protein Stability; Replication; S Phase; Structure-Activity Relationship; Tetraploidy; Transcription factors; Transcriptional Activation; Transformation, Genetic; Trichomes; Two-Hybrid System Techniques; Ubiquitin-protein ligase; Ubiquitin-Protein Ligase Complexes - genetics; Ubiquitin-Protein Ligase Complexes - metabolism; Ultraviolet radiation
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.111.091793

The anaphase-promoting complex/cyclosome (APC/C) is a multisubunit ubiquitin ligase that regulates progression through the cell cycle by marking key cell division proteins for destruction. To ensure correct cell cycle progression, accurate timing of APC/C activity is important, which is obtained through its association with both activating and inhibitory subunits. However, although the APC/C is highly conserved among eukaryotes, no APC/C inhibitors are known in plants. Recently, we have identified ULTRAVIOLET-B-INSENSITIVE4 (UVI4) as a plant-specific component of the APC/C. Here, we demonstrate that UVI4 uses conserved APC/C interaction motifs to counteract the activity of the CELL CYCLE SWITCH52 A1 (CCS52A1) activator subunit, inhibiting the turnover of the A-type cyclin CYCA2;3. UVI4 is expressed in an S phase-dependent fashion, likely through the action of E2F transcription factors. Correspondingly, uvi4 mutant plants failed to accumulate CYCA2; 3 during the S phase and prematurely exited the cell cycle, triggering the onset of the endocycle. We conclude that UVI4 regulates the temporal inactivation of APC/C during DNA replication, allowing CYCA2;3 to accumulate above the level required for entering mitosis, and thereby regulates the meristem size and plant growth rate.