Characterization of the hamster FancG/Xrcc9 gene and mutations in CHO UV40 and NM3.
Characterization of the hamster FancG/Xrcc9 gene and mutations in CHO UV40 and NM3.
复制标题
仓鼠 FancG/Xrcc9 基因的表征以及 CHO UV40 和 NM3 中的突变。
DOI：
10.1093/mutage/geh019
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发表时间：
2004
期刊：
影响因子：
2.7
通讯作者：
Thompson,LarryH
中科院分区：
文献类型：
--
作者：
Lamerdin,JaneE;Yamada,NazumiA;George,JamesW;Souza,Brian;Christian,AllenT;Jones,NigelJ;Thompson,LarryH
人类FANCG/XRCC9基因在范可尼贫血互补组G（FA-G）细胞中存在缺陷，首先通过CHO突变体UV40的丝裂霉素C（MMC）敏感性的基因互补来克隆。随后将 CHO NM3 突变体分配到相同的互补组。亲本 AA8 CHO 细胞在 FancGlocus 上是半合子，我们鉴定了导致 UV40 和 NM3 中蛋白质 N 末端截短的移码突变。对 DNA 交联剂（例如 MMC）过敏是 FA 细胞的典型特征。通过将天然CHOFancG基因引入突变体NM3，我们证明仓鼠FancG完全纠正了对甲磺酸甲酯（MMS）的3倍敏感性以及对MMC的10倍敏感性，而对电离辐射的抵抗力并没有明显增加。相反，仓鼠 cDNA 转化体对 MMC 和 MMS 敏感性的校正均不完全。组成型表达的 FancG 蛋白存在于细胞质、细胞核和染色质部分中。 FancG 蛋白水平和亚细胞定位不会随细胞周期位置发生明显变化。我们的结果与 FancG 在细胞核和细胞质区室中维持基因组稳定性以响应各种基因毒性剂的作用一致。
The humanFANCG/XRCC9gene, which is defective in Fanconi anemia complementation group G (FA‐G) cells, was first cloned by genetic complementation of the mitomycin C (MMC) sensitivity of CHO mutant UV40. The CHO NM3 mutant was subsequently assigned to the same complementation group. The parental AA8 CHO cells are hemizygous at theFancGlocus, and we identified frameshift mutations that result in N‐terminal truncations of the protein in both UV40 and NM3. Hypersensitivity to DNA cross‐linking agents, such as MMC, typically characterizes FA cells. By introducing the native CHOFancGgene into mutant NM3, we demonstrate that hamsterFancGfully corrects the 3‐fold sensitivity to methyl methanesulfonate (MMS) as well as the 10‐fold sensitivity to MMC, whereas resistance to ionizing radiation did not increase appreciably. In contrast, hamster cDNA transformants showed incomplete correction for both MMC and MMS sensitivity. The constitutively expressed FancG protein is present in the cytoplasmic, nuclear and chromatin fractions. FancG protein levels and subcellular localization do not change appreciably as a function of cell cycle position. Our results are consistent with roles of FancG in both the nuclear and cytoplasmic compartments to maintain genomic stability in response to various genotoxic agents.