Kumar Narender, Larkin John C
a Department of Biological Sciences , Louisiana State University , Baton Rouge , LA , USA.
Plant Signal Behav. 2017 Feb;12(2):e1282021. doi: 10.1080/15592324.2017.1282021.
Cell cycle regulation is fundamental to growth and development, and Cyclin-Dependent Kinase Inhibitors (CKIs) are major negative regulators of the cell cycle. Plant genomes encode substantially more CKIs than metazoan or fungal genomes. Plant CKIs fall into 2 distinct families, KIP-RELATED PROTEINS (KRPs) and SIAMESE-RELATED proteins (SMRs). SMRs can inhibit both S-phase and M-phase CDK complexes in vitro and are transcribed throughout the cell cycle, yet SMRs do not inhibit DNA replication in vivo. This suggests that SMRs must be activated post transcriptionally after the start of S-phase, but the mechanism of this hypothesized activation is unknown. Recent work indicates that even distantly related SMRs have the same biochemical function, and that differential transcriptional regulation likely maintains their distinct roles in integrating various environmental and developmental signals with the cell cycle.
细胞周期调控是生长和发育的基础，细胞周期蛋白依赖性激酶抑制剂（CKIs）是细胞周期的主要负调控因子。植物基因组编码的CKIs比后生动物或真菌基因组多得多。植物CKIs分为2个不同的家族，即KIP相关蛋白（KRPs）和SIAMESE相关蛋白（SMRs）。SMRs在体外可抑制S期和M期的CDK复合物，并且在整个细胞周期中都有转录，但SMRs在体内并不抑制DNA复制。这表明SMRs必须在S期开始后进行转录后激活，但其假设激活机制尚不清楚。最近的研究表明，即使是远缘相关的SMRs也具有相同的生化功能，差异转录调控可能维持它们在整合各种环境和发育信号与细胞周期方面的不同作用。
