hREV3基因对细胞增殖周期的影响

应用反义阻断REV3基因表达的人胚肾上皮细胞(HEK-293-M-REV3-)来研究人类REV3基因对细胞增殖周期的影响, 评价该基因在哺乳类细胞突变形成中的作用, 探讨其与肿瘤形成的关系。文章应用流式细胞技术分别对在自发或不同理化诱发条件(紫外线, UVB)和(甲基甲烷磺酸酯, MMS)]下, 对体外培养的HEK-293-M-REV3-细胞进行细胞增殖周期和DNA含量的影响进行检测, 并计算细胞的增殖指数。结果显示: 自发状态下, HEK-293-M-REV3-细胞与对照组细胞相比S期延长; 而UVB和MMS不同理化因素诱导时, HEK-293-M-REV3-细胞的G2~M期或S期比例明显比对照组增加, PI值也相应增加。因此可以推测, 当REV3基因低表达时, 细胞无论在自发还是诱发情况下突变频率均降低, 原因可能与细胞周期的改变有关, 进而再引起DNA复制叉阻滞、合成减少, 导致细胞死亡或凋亡。

Role of hREV3 in cell cycle and proliferation

Using a stable human kidney embryonic cell line HEK-293-M-REV3- in which the REV3 gene expression is suppressed by antisense RNA, we measured cell cycle progression and proliferation in an attempt to valuate the roles of REV3 in mutagenesis and tumorigenesis. HEK-293-M-REV3- cells were untreated or treated with DNA damaging agent UVB irradiation or methyl methanesulfonate (MMS), followed by flow cytometry and cell counting to determine the cell cycle distribution and proliferation index (PI). This study revealed that suppression of REV3 delayed spontaneous S phase pro-gression. When treated with MMS or UVB, HEK-293-M-REV3- cells were arrested at S or G2-M phase of the cell cycle, resulting in an increased PI. In light of our previous report that suppression of REV3 limits spontaneous and DNA dam-age-induced mutagenesis, we speculate that failure in translesion synthesis due to the abolation of DNA Polymerasex may cause frequent replication fork arrest and account for the prolonged cell cycle, which is further manifested by external sources of DNA damage. Furthermore, persistent replication fork arrest may evoke cell death or apoptosis.