分类： 核科学技术 >> 辐射物理与技术 提交时间： 2023-06-01
Li, Haoqing
Sheng, Liang
Zhang, Changqing
Du, Yingchao
Zhou, Zheng
Weng, Xiufeng
Xiao, Jiahao
Yin, Hongqiao
Sun, Bin
Wei, Kun
Li, Yang
Duan, Baojun
Liu, Yongtang
Zhang, Yanhong
Zhang, Mei
Song, Yan
Zhang, Xiaodong
Liu, Jun
Fu, Zhuming
Xu, Qing
摘要：Image distortion caused by angular misalignment of quadrupole magnets in high energy electron radiography is studied systematically. We propose that the distortion originates from the coupling of the motions of electron in transverse directions based on theoretical analysis via transfer matrix method. The relative angular rotation between the second and third magnetic quadrupoles is identified to be the main contributor to image distortion, which is verified by both beam dynamics simulation and experimental outcomes. In addition, different strategies to mitigate this image distortion are explored, including magnets online tuning, using higher beam energy and larger magnification factor. This study provides some criteria for designing experiments, and paves the way to achieve higher image precision.
分类： 生物学 >> 生物物理学 >> 细胞生物学 提交时间： 2016-05-12
Yu, Zhouliang
Zhou, Xiang
Wang, Wenjing
Deng, Wenqiang
Fang, Junnan
Hu, Hao
Wang, Zichen
Cui, Lei
Shen, Jing
Ou, Guangshuo
Yang, Na
Chen, Ping
Xu, Rui-Ming
Li, Guohong
Yu, Zhouliang
Deng, Wenqiang
Fang, Junnan
Hu, Hao
Peng, Shengyi
Li, Shangze
摘要：The H3 histone variant CENP-A is an epigenetic marker critical for the centromere identity and function. However, the precise regulation of the spatiotemporal deposition and propagation of CENP-A at centromeres during the cell cycle is still poorly understood. Here, we show that CENP-A is phosphorylated at Ser68 during early mitosis by Cdk1. Our results demonstrate that phosphorylation of Ser68 eliminates the binding of CENP-A to the assembly factor HJURP, thus preventing the premature loading of CENP-A to the centromere prior to mitotic exit. Because Cdk1 activity is at its minimum at the mitotic exit, the ratio of Cdk1/PP1 alpha activity changes in favor of Ser68 dephosphorylation, thus making CENP-A available for centromeric deposition by HJURP. Thus, we reveal that dynamic phosphorylation of CENP-A Ser68 orchestrates the spatiotemporal assembly of newly synthesized CENP-A at active centromeres during the cell cycle.
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