Department of Plant Biology, University of California, Davis, CA 95616, USA.
Biochem Biophys Res Commun. 2010 Feb 12;392(3):335-9. doi: 10.1016/j.bbrc.2010.01.020. Epub 2010 Jan 11.
The base-excision repair process protects genomes by removing and replacing altered bases in DNA. Two analogous glycosylases, oxoguanine glycosylase (OGG) and formamidopyrimidine glycosylase (FPG), can start the process by removing oxidized guanine, the most common modification that leads to misreading of DNA. Plants possess genes for both types of glycosylases. We have tested the hypothesis that the two enzymes in plants have diverged in their specificities by inserting the genes for each enzyme from Arabidopsis thaliana L. into Escherichia coli strains designed to indicate the frequencies of the six possible single-base changes. Both enzymes retain the ability to reduce the rate of GC-->TA transversion mutations. Both enzymes also reduce the frequency of two other base-change mutations, GC-->AT and AT-->TA. We do not find a divergence in the repair capabilities of the two enzymes, as measured in E. coli, although surprisingly FPG appears to increase the rate of mutations in one particular strain.
碱基切除修复过程通过去除和替换 DNA 中的改变碱基来保护基因组。两种类似的糖苷酶，即氧鸟嘌呤糖苷酶（OGG）和 N-甲酰基嘧啶糖苷酶（FPG），可以通过去除氧化的鸟嘌呤启动该过程，这是导致 DNA 误读的最常见修饰。植物具有这两种糖苷酶的基因。我们通过将来自拟南芥的每种酶的基因插入设计为指示六种可能单碱基变化频率的大肠杆菌菌株中，检验了这两种酶在特异性上已经分化的假设。两种酶都保留了降低 GC-->TA 颠换突变频率的能力。两种酶还降低了两种其他碱基变化突变（GC-->AT 和 AT-->TA）的频率。虽然令人惊讶的是，FPG 似乎增加了一个特定菌株中突变的速率，但我们没有发现这两种酶在大肠杆菌中的修复能力存在差异。
