目的细胞周期失调会导致基因组不稳定、引起细胞恶性转化和癌变。本研究通过分析乳腺癌细胞休眠期(G0期)至分裂间期细胞染色质动态行为特征,为进一步研究癌细胞周期调控提供一定的实验参考。方法以小鼠乳腺癌4T1细胞为研究对象,利用DNA...目的细胞周期失调会导致基因组不稳定、引起细胞恶性转化和癌变。本研究通过分析乳腺癌细胞休眠期(G0期)至分裂间期细胞染色质动态行为特征,为进一步研究癌细胞周期调控提供一定的实验参考。方法以小鼠乳腺癌4T1细胞为研究对象,利用DNA标记物和组蛋白相关荧光标记观察细胞染色质形态及其在细胞周期中的动态变化特征,通过激光共聚焦显微镜进行记录和分析。结果实验证实DAPI信号和GFP-H2B信号有比较好的共定位,两者均可以有效标记染色质。在细胞由G0期至分裂间期过程中,起始时可以观察到有大体积荧光标记斑块,在其中有多个着丝粒卫星DNA原位杂交斑点,而在1 h时荧光斑块逐步解离为小颗粒斑块甚至消失,到1 h 40 min时荧光标记斑块会再次出现,其体积显著小于观察起始,并规律性排布于核仁外周和核膜内侧。结论G0期乳腺癌细胞中染色质间存在聚集现象,这种聚集可能与着丝粒卫星DNA的作用相关。细胞在增值信号刺激下进入细胞周期时,染色质聚集体会逐步解聚并消失,在染色质完成复制并高度压缩形成染色体后,进一步分裂到两个子细胞。展开更多
Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activ...Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activity, indicated by the status of cerium phosphate precipitated grains, was localized mainly on the interior face （cytoplasmic side） of the PM when plants were grown under long days and reached a deep dormancy. A few reaction products were also observed on the nuclear envelope.When plant buds were developing dormancy after 28 to 42 d of SD exposure, almost no reaction products were present on the interior face of the PM. In contrast, a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM. After 70 d of SD exposure, when buds had developed a deep dormancy, the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM. The results seemed suggesting that two kinds of Ca2+-ATPases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-punlping ATPase, which is located on the interior face of the PM, for maintaining and restoring the Ca2+homeostasis. The other might be an ecto-Ca2+-ATPase, which is located on the exterior face of the PM, for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy developlnent in poplar.展开更多
文摘目的细胞周期失调会导致基因组不稳定、引起细胞恶性转化和癌变。本研究通过分析乳腺癌细胞休眠期(G0期)至分裂间期细胞染色质动态行为特征,为进一步研究癌细胞周期调控提供一定的实验参考。方法以小鼠乳腺癌4T1细胞为研究对象,利用DNA标记物和组蛋白相关荧光标记观察细胞染色质形态及其在细胞周期中的动态变化特征,通过激光共聚焦显微镜进行记录和分析。结果实验证实DAPI信号和GFP-H2B信号有比较好的共定位,两者均可以有效标记染色质。在细胞由G0期至分裂间期过程中,起始时可以观察到有大体积荧光标记斑块,在其中有多个着丝粒卫星DNA原位杂交斑点,而在1 h时荧光斑块逐步解离为小颗粒斑块甚至消失,到1 h 40 min时荧光标记斑块会再次出现,其体积显著小于观察起始,并规律性排布于核仁外周和核膜内侧。结论G0期乳腺癌细胞中染色质间存在聚集现象,这种聚集可能与着丝粒卫星DNA的作用相关。细胞在增值信号刺激下进入细胞周期时,染色质聚集体会逐步解聚并消失,在染色质完成复制并高度压缩形成染色体后,进一步分裂到两个子细胞。
文摘Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activity, indicated by the status of cerium phosphate precipitated grains, was localized mainly on the interior face （cytoplasmic side） of the PM when plants were grown under long days and reached a deep dormancy. A few reaction products were also observed on the nuclear envelope.When plant buds were developing dormancy after 28 to 42 d of SD exposure, almost no reaction products were present on the interior face of the PM. In contrast, a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM. After 70 d of SD exposure, when buds had developed a deep dormancy, the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM. The results seemed suggesting that two kinds of Ca2+-ATPases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-punlping ATPase, which is located on the interior face of the PM, for maintaining and restoring the Ca2+homeostasis. The other might be an ecto-Ca2+-ATPase, which is located on the exterior face of the PM, for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy developlnent in poplar.
