【摘要】 采用流式细胞术和 Ｎｏｒｔｈｅｒｎ ｂｌｏｔ杂交检测了 Ｘ射线照射后 ＥＬ－４细胞中 ｐ５３蛋 白及其下游基因 ＭＤＭ２ｍＲＮＡ和蛋白表达的变化，以探讨 Ｘ射线照射诱导 ＥＬ－４细胞 Ｇ１期 阻滞的分子机制。结果表明：经 ４Ｇｙ Ｘ射线照射后的 ＥＬ－４细胞， ｐ５３蛋白表达在照射后 ２ｈ增 高， ４ｈ达峰值，持续至照射后 ２４ｈ（ｐ＜ ０．０５～ ０．００１）； ＭＤＭ２蛋白的表达在照射后 ４～２４ｈ 明显升高（ｐ＜ ０．０５～ ０．０１）。进一步观察 Ｘ射线照射后 ＭＤＭ２ ｍＲＮＡ 水平的时程变化后 发现，在经 ４Ｇｙ Ｘ射线照射后的 ＥＬ－４细胞中， ＭＤＭ２ ｍＲＮＡ水平在照射后 １～８ｈ有增高 趋势，其中， ２ｈ明显升高（ｐ＜０．０１）。结果表明； Ｘ射线照射 ＥＬ－４细胞可通过 ｐ５３蛋白诱 导 ＭＤＭ２蛋白表达，从而限制 Ｇ１期阻滞的时间，使 ＤＮＡ损伤修复后的细胞重新进入细胞周 期。更多还原

【Abstract】 To explore the molecular mechanism of G1 arrest of EL-4 cells induced by whole body irradiation (WBI), Flow cytometry (FCM) and Northern blot were used to analyze p53, MDM2 gene expressions of EL-4 cells after irradiation with X-rays. Results showed that the p53 protein level of E1-4 cells increased from 2 to 24h, and the MDM2 protein level of E1-4 increased from 4 to 24h after 4Gy irradiation with X-rays. Meanwhile, the MDM2 mRNA level was sjgnificantly increased at 4h after irradiation. Conclusion: these results suggested that there was a feedback loop between p53 and MDM2 protein in EL-4 cells after irradiation with X-rays, which made G1 arrest cells reenter cell cycle.更多还原