Willingham M C, Bhalla K
Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston.
J Histochem Cytochem. 1994 Apr;42(4):441-50. doi: 10.1177/42.4.7907352.
We used a monoclonal antibody and fluorescence immunocytochemistry to localize the product of the bcl-2 gene in two cultured human carcinoma cell lines, KB and OVCAR-3. These cells show little or no localization of bcl-2 oncoprotein in interphase cells but demonstrate a dramatic appearance of bcl-2 in early prophase or late G2, which persists through-out mitosis, rapidly disappearing at telophase. The pattern of bcl-2 localization shows a diffuse nuclear distribution before chromosome condensation, followed by a specific concentration of bcl-2 at the margins of condensed chromosomes in prophase, metaphase, and anaphase. Treatment of these cells with taxol, an agent that interfers with formation of the mitotic spindle, causes mitotic arrest and apoptosis after a prolonged incubation period. During mitotic arrest due to taxol, bcl-2 remains associated with condensed chromosomes but is lost after > 2 days at approximately the same time as the appearance of apoptotic features in these cells. Western blotting indicates that the only extractable protein reactive with this monoclonal antibody under these conditions is a approximately 28 KD form of bcl-2. These results suggest a model for the role of bcl-2 in protection from apoptosis and a potentially common mechanism by which the final step of apoptosis might be mediated.
我们使用单克隆抗体和荧光免疫细胞化学方法，在两种培养的人癌细胞系KB和OVCAR-3中定位bcl-2基因的产物。这些细胞在间期细胞中几乎没有或没有bcl-2癌蛋白的定位，但在早前期或晚G2期显示出bcl-2的显著出现，这种情况在整个有丝分裂过程中持续存在，在末期迅速消失。bcl-2的定位模式在染色体浓缩之前显示出弥漫性核分布，随后在前期、中期和后期浓缩染色体的边缘出现bcl-2的特定聚集。用紫杉醇（一种干扰有丝分裂纺锤体形成的药物）处理这些细胞，在长时间孵育后会导致有丝分裂停滞和凋亡。在由于紫杉醇导致的有丝分裂停滞期间，bcl-2仍然与浓缩染色体相关，但在约2天后随着这些细胞中凋亡特征的出现而消失。蛋白质免疫印迹法表明，在这些条件下与该单克隆抗体反应的唯一可提取蛋白是一种约28KD形式的bcl-2。这些结果提示了一个bcl-2在抗凋亡中作用的模型，以及一种可能介导凋亡最后一步的潜在共同机制。
