Heyman Jefri, Polyn Stefanie, Eekhout Thomas, De Veylder Lieven
Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium and Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium.
Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium and Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
Plant Physiol. 2017 Sep;175(1):303-313. doi: 10.1104/pp.17.00785. Epub 2017 Jul 11.
The endocycle represents a modified mitotic cell cycle that in plants is often coupled to cell enlargement and differentiation. Endocycle onset is controlled by activity of the Anaphase Promoting Complex/Cyclosome (APC/C), a multisubunit E3 ubiquitin ligase targeting cell-cycle factors for destruction. CELL CYCLE SWITCH52 (CCS52) proteins represent rate-limiting activator subunits of the APC/C. In Arabidopsis (), mutations in either or activators result in a delayed endocycle onset, whereas their overexpression triggers increased DNA ploidy levels. Here, the relative contribution of the APC/C and APC/C complexes to different developmental processes was studied through analysis of their negative regulators, being the ULTRAVIOLET-B-INSENSITIVE4 protein and the DP-E2F-Like1 transcriptional repressor, respectively. Our data illustrate cooperative activity of the APC/C and APC/C complexes during root and trichome development, but functional interdependency during leaf development. Furthermore, we found APC/C activity to control expression. We conclude that interdependency of CCS52A-controlled APC/C activity is controlled in a tissue-specific manner.
内循环代表一种经过修饰的有丝分裂细胞周期，在植物中它通常与细胞扩大和分化相关联。内循环的起始由后期促进复合体/细胞周期体（APC/C）的活性控制，APC/C是一种多亚基E3泛素连接酶，可靶向细胞周期因子进行降解。细胞周期开关52（CCS52）蛋白是APC/C的限速激活亚基。在拟南芥中，CCS52A或CCS52B激活因子的突变会导致内循环起始延迟，而它们的过表达则会引发DNA倍性水平的增加。在这里，通过分析APC/C和APC/C复合体的负调控因子，即紫外线B不敏感4蛋白和DP-E2F样1转录抑制因子，研究了它们对不同发育过程的相对贡献。我们的数据表明，APC/C和APC/C复合体在根和毛状体发育过程中具有协同活性，但在叶片发育过程中存在功能相互依赖性。此外，我们发现APC/C活性可控制CCS52A的表达。我们得出结论，CCS52A控制的APC/C活性的相互依赖性是以组织特异性方式控制的。
