植物D型细胞周期蛋白

Plant D-type Cyclins

D型细胞周期蛋白(cyclinD,CycD)调控着细胞周期G1/S的转换,基本过程为CycD在外界环境刺激下积累,并与周期蛋白依赖激酶(cyclin-dependentkinase,CDK)形成有活性的激酶,促进成视网膜细胞瘤蛋白(retinoblastoma,Rb)磷酸化,使E2F因子释放,由此促使G1/S转换,这一调控系统在高等真核生物中具有很高的保守性。CycD与其他细胞周期蛋白表达有所不同,其受到生长因子的强烈诱导,去掉生长因子后,表达水平迅速下降,导致细胞被抑制在G1期。大量研究表明,CycD是细胞周期中一个关键的“感受因子”,CycD基因的表达是细胞周期进程中的限速因子,影响着植物的生长发育。现对植物CycD的特征以及在细胞周期中的功能进行综述,并探讨了其在植物生长发育中的作用。

D-type cyclin （cyclinD, CycD） regulates the G1/S transition. Under the stimulation of the exogenous signals, CycD accumulates and binds to cyclin dependent kinase （CDK） to form active complexes, which phosphorylate the retinoblastoma （Rb） protein. Rb phosphorylation results in releasing the transcription fac- tor E2F and thereby drives the G1/S transition. The control pathway is conserved in all higher eukaryotes. CycDs are different from other cyclins, because their expression is not tightly cell-cycle-regulated, but rather is activated by growth factors and decline rapidly when the mitogenic signal is removed, therefore the cell is arrested in G1. Many analyses showed that CycDs are crucial growth factor sensor, the expression of these genes affects plant development. Here we reviewed the characteristics and roles in cell cycle of plant CycDs, and discussed their functions in plant development.