INK4A基因及P16蛋白在辐射诱导小鼠白血病模型中的变化

Alterations of INK4A gene and P16 protein in leukemia mice model induced by ^60 Co γ-ray irradiation

目的研究INK4A基因及编码的P16蛋白在辐射诱导的小鼠白血病模型中的改变。方法7．0Gy^60Coγ射线分4次照射BALB／c小鼠建立辐射诱导的小鼠白血病模型；PCR扩增INK4A基因第1、第2外显子，俭测等位基凶纯合性缺失，甲基化敏感酶切PCR法检测INK4A基因的甲基化发隹情况，并应用PCR单链构象多态性分析方法检测碱基突变的发生；Westernblot检测P16蛋白含量改变。结果在21例白血病模型组织中，外显子2缺失5例，4例发生甲基化，有11例蛋白表达明显下降。结论辐射诱导的小鼠白血病模型发生过程中伴有P16蛋白表达下降，INK4A基因改变以纯合性缺失和甲基化为主。

Objective To investigate the alterations of INK4A gene and protein in the leukemia model of mice induced by ^60 Co γ-ray irradiation. Methods BALB/c mice were irradiated 4 times weekly with ^60 Co γ-ray irradiation to establish the animal model of lymphocyte leukemia, and the total absorbed dose was 7.0 Cy. PCR was used to amplify exons 1 and 2 of iNK4A gene and to detect the homozygous deletion. The occurrence of methylation in the 5＇CpG island was studied with methylation sensitive enzyme PCR. PCR-SSCP-silver staining technique was used to detect the mutation. The expression of P16 protein was detected with Western blot. Results In 21 cases of leukemia model tissues, there were 5 cases of depletion of the exon 2 of INK4A gene, and 4 cases of methylation in the priming domain of the exon 1, 11 cases of protein expression decreased. Conclusions The decrease in p16 expression might participate in the radiation- induced tumorigenesis. The homozygous deletion and methylation are the main causes of inactivation of INK4A gene in mice.