The Research Of APC/C Degradation Mechanism In Cell Cycle Regulation

The discovery of protein degradation through the ubiquitin proteasome pathway in recent years,opened a new chapter on the mechanism research of Cyclin degradation by APC/C.Therefore,the research of Cyclin degradation mechanism by the ubiquitin proteasome pathway is of great significance.According to the literature, APC/Cdh1plays a major role in G1phase, with a highly active in order to guarantees the Cyclin don’t accumulate too early and keeps cells in G1phase.APC/Cdc20plays a major role in M phase. In M phase,APC/Cdc20initiates the metaphase-anaphase transition, promotes separation of sister chromatids and mitotic exit.In this paper, based on experimental phenomena, First of all, we used original model of CycB-Cdh1-Cdc20, respectively to study the the influence of Cdh1synthesis rate in the G1phase and the cell cycle time. The study found that the increase or decrease of Cdh1synthesis rate will bring G1phase delay or shorten,but has no effect on M phase. secondly,we used the hybrid approach that combined the best features of continuous differential equations and discrete boolean networks. The concentration of Cyclin are tracked by piecewise linear differential equations for Cyclin synthesis and degradation., the transcription factors TFB whose activities are represented by discrete variables (0or1) and likewise for the activities of Cdh1and Cdc20complexes that govern Cyclin degradation. Then,we build a discrete and continuous model of CycB-Cdh1-Cdc20,respectively to study the cell cycle under normal condition and the loss of Cdh1in G1phase as well the loss of Cdc20in M phase. Found that when Cdh1loss in G1phase,the time of G1phase is shortened, and Cdc20missing in M phase induced the cells cannot be divided, this consequence is consistent with the experimental phenomena.