Otsuka Chie, Sanadai Sachi, Hata Yasuhiro, Okuto Hisanori, Noskov Vladimir N, Loakes David, Negishi Kazuo
Gene Research Center, Okayama University, Tsushima, Okayama 700-8530, Japan, National Cancer Institute, Bethesda, MD 20892, USA and. Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
Nucleic Acids Res. 2002 Dec 1;30(23):5129-35. doi: 10.1093/nar/gkf666.
We have analyzed the mutagenic specificity of an abasic site in DNA using the yeast oligonucleotide transformation assay. Oligonucleotides containing an abasic site or its analog were introduced into B7528 or its derivatives, and nucleotide incorporation opposite abasic sites was analyzed. Cytosine was most frequently incorporated opposite a natural abasic site (O) ('C-rule'), followed by thymine. Deletion of REV1 decreased the transformation efficiency and the incorporation of cytosine nearly to a background level. In contrast, deletion of RAD30 did not affect them. We compared the mutagenic specificity with that of a tetrahydrofuran abasic site (F), an abasic analog used widely. Its mutation spectrum was clearly different from that of O. Adenine, not cytosine, was most favorably incorporated. However, deletion of REV1 decreased the transformation efficiency with F-containing oligonucleotide as in the case of O. These results suggest that the bypass mechanism of F is different from that of O, although the bypasses in both cases are dependent on REV1. We also found that the mutagenic specificity of F can be affected by not only the adjacent bases, but also a base located two positions away from F.
我们使用酵母寡核苷酸转化试验分析了DNA中无碱基位点的诱变特异性。将含有无碱基位点或其类似物的寡核苷酸导入B7528或其衍生物中，并分析无碱基位点对面的核苷酸掺入情况。胞嘧啶最常掺入天然无碱基位点（O）对面（“C规则”），其次是胸腺嘧啶。REV1的缺失使转化效率和胞嘧啶的掺入几乎降至背景水平。相比之下，RAD30的缺失对它们没有影响。我们将诱变特异性与广泛使用的无碱基类似物四氢呋喃无碱基位点（F）的诱变特异性进行了比较。其突变谱与O的明显不同。最容易掺入的是腺嘌呤，而不是胞嘧啶。然而，与O的情况一样，REV1的缺失降低了含F寡核苷酸的转化效率。这些结果表明，F的跨越机制与O不同，尽管两种情况下的跨越都依赖于REV1。我们还发现，F的诱变特异性不仅会受到相邻碱基的影响，还会受到距离F两个位置的碱基的影响。
