Kow Yoke W, Bao Gaobin, Minesinger Brenda, Jinks-Robertson Sue, Siede Wolfram, Jiang Yu Lin, Greenberg Marc M
Department of Radiation Oncology, Emory University School of Medicine, 1365-B Clifton Road NE, Suite B5119, Atlanta, GA 30322, USA.
Nucleic Acids Res. 2005 Oct 27;33(19):6196-202. doi: 10.1093/nar/gki926. Print 2005.
2-deoxyribonolactone (L) and 2-deoxyribose (AP) are abasic sites that are produced by ionizing radiation, reactive oxygen species and a variety of DNA damaging agents. The biological processing of the AP site has been examined in the yeast Saccharomyces cerevisiae. However, nothing is known about how L is processed in this organism. We determined the bypass and mutagenic specificity of DNA containing an abasic site (AP and L) or the AP analog tetrahydrofuran (F) using an oligonucleotide transformation assay. The tetrahydrofuran analog and L were bypassed at 10-fold higher frequencies than the AP lesions. Bypass frequencies of lesions were greatly reduced in the absence of Rev1 or Polzeta (rev3 mutant), but were only marginally reduced in the absence of Poleta (rad30 mutant). Deoxycytidine was the preferred nucleotide inserted opposite an AP site whereas dA and dC were inserted at equal frequencies opposite F and L sites. In the rev1 and rev3 strains, dA was the predominant nucleotide inserted opposite these lesions. Overall, we conclude that both Rev1 and Polzeta are required for the efficient bypass of abasic sites in yeast.
2-脱氧核糖内酯（L）和2-脱氧核糖（AP）是由电离辐射、活性氧和多种DNA损伤剂产生的无碱基位点。已在酿酒酵母中研究了AP位点的生物学处理过程。然而，关于该生物体中L如何被处理却一无所知。我们使用寡核苷酸转化测定法确定了含有无碱基位点（AP和L）或AP类似物四氢呋喃（F）的DNA的跨越和诱变特异性。四氢呋喃类似物和L的跨越频率比AP损伤高10倍。在没有Rev1或Polzeta（rev3突变体）的情况下，损伤的跨越频率大大降低，但在没有Poleta（rad30突变体）的情况下仅略有降低。脱氧胞苷是插入到AP位点对面的首选核苷酸，而dA和dC以相等的频率插入到F和L位点对面。在rev1和rev3菌株中，dA是插入到这些损伤对面的主要核苷酸。总体而言，我们得出结论，Rev1和Polzeta都是酵母中有效跨越无碱基位点所必需的。
