Defining the restriction point in normal asynchronous human peripheral blood lymphocytes

Authors

  • Jianwu Jiang,

    1. Department of Surgery and Molecular Medical Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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    • J. Jiang and L. Liu contributed equally to this work.

  • Liang Liu,

    1. Department of Surgery and Molecular Medical Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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    • J. Jiang and L. Liu contributed equally to this work.

  • Xiaolan Li,

    1. Department of Surgery and Molecular Medical Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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  • Deding Tao,

    1. Department of Surgery and Molecular Medical Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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  • Junbo Hu,

    1. Department of Surgery and Molecular Medical Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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  • Jichao Qin

    Corresponding author
    • Department of Surgery and Molecular Medical Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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Correspondence to: Jichao Qin, Department of Surgery and Molecular Medical Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China. E-mail: jcqin@tjh.tjmu.edu.cn

Abstract

Although the restriction point (R-point) was proposed in animal cells several decades ago, its existence in normal cells is still controversial, because, in most studies, long-term cultured cell lines rather than primary normal cells were used. Furthermore, cell synchronization was generally applied, resulting in growth imbalance between DNA synthesis and protein expression in cells. Finally, R-point was originally proposed as a unique arrest point that may be in G0 phase; however, generally believed R-point locates within G1 phase. Thus, up to now, there is no solid experimental evidence that supports the existence of R-point in asynchronous primary normal cells. In this study, we used freshly purified peripheral human blood lymphocytes, as asynchronous primary normal cells, to confirm the existence of restriction point in G1 not G0 phase. Our findings may help uncover the mystery of the deregulation of cell cycle progression in malignant tumors. © 2013 International Society for Advancement of Cytometry

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