CtBP-interacting protein(CtIP)is known for its multifaceted roles in DNA repair and genomic stability,directing the homologous recombination-mediated DNA double-stranded break repair pathway via DNA end resection,an e...CtBP-interacting protein(CtIP)is known for its multifaceted roles in DNA repair and genomic stability,directing the homologous recombination-mediated DNA double-stranded break repair pathway via DNA end resection,an essential error-free repair process vital for genome stability.Mammalian oocytes are highly prone to DNA damage accumulation due to prolonged G2/prophase arrest.Here,we explore the functions of CtIP in meiotic cell cycle regulation via a mouse oocyte model.Depletion of CtIP by siRNA injection results in delayed germinal vesicle breakdown and failed polar body extrusion.Mechanistically,CtIP deficiency increases DNA damage and decreases the expression and nuclear entry of CCNB1,resulting in marked impairment of meiotic resumption,which can be rescued by exogenous CCNB1 overexpression.Furthermore,depletion of CtIP disrupts microtubule-organizing centers coalescence at spindle poles as indicated by failed accumulation ofγ-tubulin,p-Aurora kinase A,Kif2A,and TPX2,leading to abnormal spindle assembly and prometaphase arrest.These results provide valuable insights into the important roles of CtIP in the G2/M checkpoint and spindle assembly in mouse oocyte meiotic cell cycle regulation.展开更多
As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functi...As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functional characterization of the CDC5 gene in Arabidopsis thaliana. Arabidopsis CDC5 （AtCDC5） is mainly expressed in tissues with high cell division activity, and is expressed throughout the entire process of embryo formation. The AtCDC5 loss-of-function mutant is embryonic lethal. In order to investigate the function of AtCDC5 in vivo, we generated AtCDC5-RNAi plants in which the expression of AtCDC5 was reduced by RNA interference. We found that the G2 to M （G2/M） phase transition was affected in the AtCDC5-RNAi plants, and that endoreduplication was increased. Additionally, the maintenance of shoot apical meristem （SAM） function was disturbed in the AtCDC5-RNAi plants, in which both the WUSCHEL （WUS）- CLAVATA （CLV） and the SHOOT MERISTEMLESS （STM） pathways were impaired. In situ hybridization analysis showed that the expression of STMwas greatly reduced in the shoot apical cells of the AtCDC5-RNAi plants. Moreover, cyclinB1 or Histone4 was found to be expressed in some of these cells when the transcript of STM was undetectable. These results suggest that AtCDC5 is essential for the G2/M phase transition and may regulate the function of SAM by controlling the expression ofSTMand WUS.展开更多
In order to smooth the trajectory of a robot and reduce dwell time,a transition curve is introduced between two adjacent curves in three-dimensional space.G2 continuity is guaranteed to transit smoothly.To minimize th...In order to smooth the trajectory of a robot and reduce dwell time,a transition curve is introduced between two adjacent curves in three-dimensional space.G2 continuity is guaranteed to transit smoothly.To minimize the amount of calculation,cubic and quartic Bezier curves are both analyzed.Furthermore,the contour curve is characterized by a transition parameter which defines the distance to the corner of the deviation.How to define the transition points for different curves is presented.A general move command interface is defined for receiving the curve limitations and transition parameters.Then,how to calculate the control points of the cubic and quartic Bezier curves is analyzed and given.Different situations are discussed separately,including transition between two lines,transition between a line and a circle,and transition between two circles.Finally,the experiments are carried out on a six degree of freedom(DOF) industrial robot to validate the proposed method.Results of single transition and multiple transitions are presented.The trajectories in the joint space are also analyzed.The results indicate that the method achieves G2 continuity within the transition constraint and has good efficiency and adaptability.展开更多
基金supported by National Natural Science Foundation of China(32570854)Science and Technology Program of Guangzhou,China(2023A03J0258)Guangdong Basic and Applied Basic Research Foundation,China(2023B1515120027)。
文摘CtBP-interacting protein(CtIP)is known for its multifaceted roles in DNA repair and genomic stability,directing the homologous recombination-mediated DNA double-stranded break repair pathway via DNA end resection,an essential error-free repair process vital for genome stability.Mammalian oocytes are highly prone to DNA damage accumulation due to prolonged G2/prophase arrest.Here,we explore the functions of CtIP in meiotic cell cycle regulation via a mouse oocyte model.Depletion of CtIP by siRNA injection results in delayed germinal vesicle breakdown and failed polar body extrusion.Mechanistically,CtIP deficiency increases DNA damage and decreases the expression and nuclear entry of CCNB1,resulting in marked impairment of meiotic resumption,which can be rescued by exogenous CCNB1 overexpression.Furthermore,depletion of CtIP disrupts microtubule-organizing centers coalescence at spindle poles as indicated by failed accumulation ofγ-tubulin,p-Aurora kinase A,Kif2A,and TPX2,leading to abnormal spindle assembly and prometaphase arrest.These results provide valuable insights into the important roles of CtIP in the G2/M checkpoint and spindle assembly in mouse oocyte meiotic cell cycle regulation.
基金Acknowledgments The authors thank Dr Liying Du （Peking University, China） for technical help on the flow cytometric analysis. The authors also thank Dr Zhongchi Liu （University of Maryland, USA）, Dr Chun-Ming Liu （Institute of Botany CAS, China）, Dr Terry Matthew （University of Southampton, UK）, Professor Daochun Kong （Peking University, China） and Dr Naomi Nakayama （Yale University, USA） for critical comments and valuable discussion. This work was supported by the National Natural Science Foundation of China （GN 30625002 to L-J Qu）.
文摘As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functional characterization of the CDC5 gene in Arabidopsis thaliana. Arabidopsis CDC5 （AtCDC5） is mainly expressed in tissues with high cell division activity, and is expressed throughout the entire process of embryo formation. The AtCDC5 loss-of-function mutant is embryonic lethal. In order to investigate the function of AtCDC5 in vivo, we generated AtCDC5-RNAi plants in which the expression of AtCDC5 was reduced by RNA interference. We found that the G2 to M （G2/M） phase transition was affected in the AtCDC5-RNAi plants, and that endoreduplication was increased. Additionally, the maintenance of shoot apical meristem （SAM） function was disturbed in the AtCDC5-RNAi plants, in which both the WUSCHEL （WUS）- CLAVATA （CLV） and the SHOOT MERISTEMLESS （STM） pathways were impaired. In situ hybridization analysis showed that the expression of STMwas greatly reduced in the shoot apical cells of the AtCDC5-RNAi plants. Moreover, cyclinB1 or Histone4 was found to be expressed in some of these cells when the transcript of STM was undetectable. These results suggest that AtCDC5 is essential for the G2/M phase transition and may regulate the function of SAM by controlling the expression ofSTMand WUS.
基金Supported by the National Natural Science Foundation of China(No.61573358)Research and Development of Large Multi-function Demolition Equipment in Disaster Site(No.2015BAK06B00)
文摘In order to smooth the trajectory of a robot and reduce dwell time,a transition curve is introduced between two adjacent curves in three-dimensional space.G2 continuity is guaranteed to transit smoothly.To minimize the amount of calculation,cubic and quartic Bezier curves are both analyzed.Furthermore,the contour curve is characterized by a transition parameter which defines the distance to the corner of the deviation.How to define the transition points for different curves is presented.A general move command interface is defined for receiving the curve limitations and transition parameters.Then,how to calculate the control points of the cubic and quartic Bezier curves is analyzed and given.Different situations are discussed separately,including transition between two lines,transition between a line and a circle,and transition between two circles.Finally,the experiments are carried out on a six degree of freedom(DOF) industrial robot to validate the proposed method.Results of single transition and multiple transitions are presented.The trajectories in the joint space are also analyzed.The results indicate that the method achieves G2 continuity within the transition constraint and has good efficiency and adaptability.
