Harper Adams University College, Newport, Shropshire TF10 8NB, UK.
Mutagenesis. 2013 Jul;28(4):393-9. doi: 10.1093/mutage/get015. Epub 2013 Mar 9.
Expression of the human GADD45a gene is increased in TK6 cells exposed to mutagens, clastogens and aneugens. It is known to be regulated through both p53-dependent and p53-independent pathways and WT1 has been implicated in both cases. This article reports an investigation into the effect that mutations in the WT1 and p53 response elements of the gene have on GADD45a expression. This was conducted in both p53 wild-type (TK6) and mutant (WI-L2-NS) human B lymphoblastoid cell lines. Gene expression was monitored using a GADD45a-green fluorescent protein reporter assay. Mutant cell lines were exposed to the mechanistically diverse genotoxins methyl methanesulphonate, cisplatin and mitomycin C (direct acting), hydroxyurea, aphidicolin and 5'fluorouracil (inhibitors of nucleotide/DNA synthesis) and benomyl (aneugen). In all cases, the induction of the reporter was reduced in the mutants compared with wild-type. These results provide experimental evidence for the implied role of WT1 in both p53-dependent and p53-independent pathways of GADD45a regulation and further insight into the mechanism of GADD45a induction by genotoxins.
人 GADD45a 基因的表达在暴露于诱变剂、断裂剂和非整倍体剂的 TK6 细胞中增加。已知它通过 p53 依赖性和 p53 非依赖性途径进行调节，WT1 已被牵连到两种情况中。本文报告了对基因中 WT1 和 p53 反应元件突变对 GADD45a 表达影响的研究。这在 p53 野生型（TK6）和突变型（WI-L2-NS）人 B 淋巴母细胞系中进行。使用 GADD45a-绿色荧光蛋白报告基因测定法监测基因表达。将突变细胞系暴露于机制上不同的遗传毒物甲磺酸甲酯、顺铂和丝裂霉素 C（直接作用）、羟基脲、阿非迪霉素和 5'氟尿嘧啶（核苷酸/DNA 合成抑制剂）和苯并咪唑（非整倍体剂）。在所有情况下，与野生型相比，报告基因的诱导在突变体中降低。这些结果为 WT1 在 GADD45a 调节的 p53 依赖性和 p53 非依赖性途径中的隐含作用提供了实验证据，并进一步深入了解遗传毒物诱导 GADD45a 的机制。
