Detection of cyclin B1 expression in G1-phase cancer cell lines and cancer tissues by postsorting western blot analysis
Detection of cyclin B1 expression in G1-phase cancer cell lines and cancer tissues by postsorting western blot analysis
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DOI：
10.1158/0008-5472.can-03-3321
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发表时间：
2004-03-01
期刊：
影响因子：
11.2
通讯作者：
Gong, JP
中科院分区：
文献类型：
--
作者：
Shen, ML;Feng, YD;Gong, JP
细胞周期蛋白B1和细胞周期蛋白依赖性蛋白激酶1的蛋白复合物诱导介导细胞周期G（2）-M期转换的关键底物的磷酸化。据信，细胞周期蛋白B1在细胞周期的S期积累，并在有丝分裂时达到最高水平，但在G（1）期细胞中不存在。在本研究中，我们证明，细胞周期蛋白B1的表达在G（1）-期MOLT-4淋巴细胞白血病细胞和G（1）期T-7移行肿瘤细胞，通过流式细胞术测定。此外，我们还发现，在患者组织的乳腺癌细胞和白血病患者的淋巴细胞中，细胞周期蛋白B1处于G（1）期。这些发现证实了第一次通过后分选蛋白质印迹分析和共聚焦显微镜。此外，通过分选后的Western blotting，我们发现在不同的条件下，cyclin B1在G（1）期的不同时间窗部分表达。在非同步生长的T-7细胞中，cyclin B1主要表达于G（1）早期，而在阻滞于G（1）-S期的MOLT-4细胞中，cyclin B1主要表达于G（1）晚期。我们认为，周期蛋白B1在G（1）期的表达可能不同于在G（2）-M期的表达，这种非程序型的周期蛋白B1可能在肿瘤发生和凋亡中起重要作用。
Protein complex of cyclin B1 and cyclin-dependent protein kinase 1 induces phosphorylation of key substrates that mediate cell cycle transition during the G(2)-M phase. It is believed that cyclin B1 accumulates in the S phase of the cell cycle and reaches the maximal level at mitosis but is absent in G(1)-phase cells. In the present study, we demonstrated that cyclin B1 was expressed in the arrested G(1)-phase MOLT-4 lymphocyte leukemia cells and in G(1) phase T-7 transitional tumor cells, as determined by flow cytometry. In addition, we showed that cyclin B1 was detected in the G(1) phase in breast cancer cells from patient tissues and in lymphocytes from patients with leukemia. These findings were confirmed for the first time by postsorting Western blot analysis and by confocal microscopy. Furthermore, by using postsorting Western blotting, we found that cyclin B1 was expressed in different time-window sections of the G(1) phase under different conditions. For the asynchronously growing T-7 cells, cyclin B1 was detected in early G(1) phase, whereas in MOLT-4 cells arrested in G(1)-S phase, cyclin B1 was mainly detected in late G(1) phase. We propose that the cyclin B1 expressed in the G(1) phase may differ from that expressed in the G(2)-M phase, and that this unscheduled type of cyclin B1 may play an important role in tumorigenesis and apoptosis.