小鼠成纤维细胞凋亡过程中P53与bcl-2表达的时序性

为探讨细胞凋亡过程中，ｂｃｌ－２与Ｐ５３，这两种凋亡关键性基因的相互关系，用５－氟尿嘧啶（５－Ｆｕ）诱导小鼠正常与恶性转化的成纤维细胞的凋亡，观察了这两种基因在凋亡过程中表达变化的时序．经流式细胞计检测，这两种细胞在５－Ｆｕ作用２４ｈ均出现了凋亡峰，细胞存活率随之下降，ＤＮＡ电泳显现梯状断裂．Ｎｏｒｔｈｅｒｎ杂交结果显示，在５－Ｆｕ作用６ｈ后两种细胞Ｐ５３ｍＲＮＡ水平已明显增高，而ｂｃｌ－２ｍＲＮＡ水平则在作用１２ｈ方明显降低．Ｐ５３上调与ｂｃｌ－２下调的明显时序性，说明Ｐ５３具备作为ｂｃｌ－２基因负调控转录因子的条件．由此，为进一步了解凋亡过程的ｂｃｌ－２基因下调机理提供了线索

The Time Order of P53 and bcl 2 Gene Expression in the Apoptotic Process of Mouse Fibroblast Cell Lines

To explore the time order of expression of p53 and bcl 2 genes in apoptotic process,apoptosis of C3H mouse embryo fibroblast cell lines(C3H 10T1/2 Cl 8,designated as NC3H10,and its tritium transformed counterpart,designated as TC3H10)were induced by 5 fluorouracil (5 Fu).DNA ladders appeared after exposing both cell lines to 5 Fu for 48 h.Flow cytometry analysed results revealed that apoptotic peak appeared after 5 Fu treatment for 24 h,and it was much more pronounced after 5 Fu treatment for 48 h.Northern blotting results showed that P53 mRNA level increased significantly after exposing both cells to 5 Fu for 6 h,while bcl 2 mRNA level decreased significantly after 5 Fu treatment for 12 h.The apparent time order of P53 and bcl 2 genes expression in both cells suggested that P53 might have to do something with down regulating of bcl 2 gene.These results provided a clue for the research of bcl 2's down regulation.