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为了研究N-乙酰氨基葡萄糖基转移酶(GlcNAc-T)Ⅲ,Ⅳ和Ⅴ在细胞周期中的变化,采用血清饥饿法对7721人肝癌细胞进行同步化培养,用流式细胞仪(FCM)测定处于不同生长期的细胞比例,同时测定P34~(cdc2)激酶活性验证细胞周期。GlcNAc-TⅢ的活性在G_0/G_1期细胞的高峰时相较高,与该期的细胞百分比存在着明显的相关性(r=0.760,P<0.05),而GlcNAc-T Ⅴ活性的升高出现在G_2/M期细胞最多的时相,且与该期的细胞百分比间亦存有明显的相关性(r=0.868,P<0.001)。GlcNAc-T Ⅳ的活性改变与细胞周期关系不大。GlcNAc-T Ⅲ和GlcNAc-T Ⅴ在细胞周期中的变化呈现出相反的趋势(r=-0.951,P<0.001),提示GlcNAc-T Ⅲ可能与细胞分裂的静止有关,或者说是抗增殖的,而GlcNAc-T Ⅴ则可能与细胞的增殖有关。用免疫组化法发现GlcNAc-TⅤ的蛋白含量在整个细胞周期中无明显改变,与酶活性之间无相关性存在,故此酶在细胞周期中活性变化不是由酶蛋白合成改变而引起的。GlcNAc-T Ⅴ其活性在细胞周期中的变化与p34~(cdc2)激酶活性改变相一致(r=0.752,P<0.05),推测该酶的活性变化可能受到p34~(cdc2)激酶的调控。
To study the changes of N-acetylglucosaminyltransferase (GlcNAc-T) III, IV, and V in the cell cycle, 7721 human hepatoma cells were cultured synchronously by serum starvation and measured by flow cytometry (FCM). The proportion of cells in different growth phases, simultaneous determination of P34~(cdc2) kinase activity verified the cell cycle. The activity of GlcNAc-TIII was higher in the peak phase of G 0 /G 1 phase cells, and there was a significant correlation with the percentage of cells in this phase (r=0.760, P<0.05), while the elevation of GlcNAc-T V activity appeared. The phase with the most cells in G2/M phase had a significant correlation with the percentage of cells in this phase (r=0.868, P<0.001). The change in activity of GlcNAc-T IV has little to do with the cell cycle. The change of GlcNAc-T III and GlcNAc-T V in the cell cycle showed the opposite trend (r=-0.951, P<0.001), suggesting that GlcNAc-T III may be involved in the quiescence of cell division, or anti-proliferative However, GlcNAc-T V may be related to cell proliferation. Immunohistochemical method revealed that the protein content of GlcNAc-TV did not change significantly throughout the cell cycle, and there was no correlation between the activity of the enzyme and the activity of the enzyme. Therefore, the activity change of the enzyme in the cell cycle was not caused by the change of enzyme protein synthesis. The activity of GlcNAc-T V in the cell cycle was consistent with that of p34~(cdc2) kinase activity (r=0.752, P<0.05). It is speculated that the activity of this enzyme may be regulated by the p34~(cdc2) kinase.