P2P-R protein localizes to the nucleolus of interphase cells and the periphery of chromosomes in mitotic cells which show maximum P2P-R immunoreactivity
P2P-R protein localizes to the nucleolus of interphase cells and the periphery of chromosomes in mitotic cells which show maximum P2P-R immunoreactivity
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DOI：
10.1002/jcp.10084
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发表时间：
2002-05-01
影响因子：
5.6
通讯作者：
Scott, RE
中科院分区：
文献类型：
--
作者：
Gao, SZ;Witte, MM;Scott, RE
P2P-R是一种核蛋白，可以结合p53和Rb1。它的功能包括控制RNA代谢、细胞凋亡和p53依赖性转录。在G(1)阻滞的终末分化细胞中，P2P-R的表达也受到抑制。因此，目前的研究评估了P2P-R的丰度和/或定位是否经历了细胞周期相关的变化。Western blots结果显示，与Go静止细胞相比，通过血清剥夺-血清刺激生理同步技术制备的G(2)/M细胞群体的P2P-R蛋白水平更高。更引人注目的是，通过有丝分裂震动选择技术或与有丝分裂纺锤体破坏剂诺可唑或长春碱同步制备的高度纯化的有丝分裂细胞标本中，p2 - r蛋白的富集程度达到了10倍。这些P2P-R蛋白的变化没有伴随P2P-R mRNA表达的变化，这表明P2P-R免疫反应性在有丝分裂期间增加。接下来，共聚焦显微镜确定了P2P-R在间期细胞和缺乏核仁的有丝分裂细胞中染色体边缘的核仁定位。在有丝分裂细胞中，高水平的P2P-R定位于染色体外周，这表明P2P-R与有丝分裂过程中与染色体外周相关的其他核仁蛋白具有相同的特征。这些包括：核仁蛋白、B23、Ki67和纤维蛋白。(C) 2002 Wiley-Liss, Inc。
P2P-R is a nuclear protein that can bind both p53 and Rb1. Its functions include roles in the control of RNA metabolism, apoptosis, and p53-dependent transcription. The expression of P2P-R also is repressed in G(1) arrested terminally differentiated cells. The current studies therefore evaluated if P2P-R undergoes cell cycle-associated changes in its abundance and/or localization. Western blots show that relative to Go quiescent cells, P2P-R protein levels are higher in populations of G(2)/M cells prepared by the physiological parasynchronization technique of serum deprivation followed by serum stimulation. More striking is the > 10-fold enrichment of P2P-R protein in specimens of highly purified mitotic cells prepared by the mitotic shake-select technique, or by synchrony with the mitotic spindle disruption agents nocodazole or vinblastine. These changes in P2P-R protein occur without a concomitant change in P2P-R mRNA expression suggesting that P2P-R immunoreactivity increases during mitosis. Confocal microscopy next established the localization of P2P-R to nucleoli in interphase cells and at the periphery of chromosomes in mitotic cells that lack nucleoli. The high levels of P2P-R localized to the periphery of chromosomes in mitotic cells suggest that P2P-R shares characteristics with other nucleolar proteins that associate with the periphery of chromosomes during mitosis. These include: nucleolin, B23, Ki67, and fibrillarin. (C) 2002 Wiley-Liss, Inc.