Tsuruta Haruka, Sonohara Yuina, Tohashi Kosuke, Aoki Shioi Narumi, Iwai Shigenori, Kuraoka Isao
1Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180 Japan.
2Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 Japan.
Genes Environ. 2020 Jan 6;42:2. doi: 10.1186/s41021-019-0142-7. eCollection 2020.
Acetaldehyde, produced upon exposure to alcohol, cigarette smoke, polluted air and sugar, is a highly reactive compound that is carcinogenic to humans and causes a variety of DNA lesions in living human cells. Previously, we reported that acetaldehyde reacts with adjacent deoxyguanosine residues on oligonucleotides, but not with single deoxyguanosine residues or other deoxyadenosine, deoxycytosine, or thymidine residues, and revealed that it forms reversible intrastrand crosslinks with the dGpdG sequence (GG dimer).
Here, we show that restriction enzymes that recognize a GG sequence digested acetaldehyde-treated plasmid DNA with low but significant efficiencies, whereas restriction enzymes that recognize other sequences were able to digest such DNA. This suggested that acetaldehyde produced GG dimers in plasmid DNA. Additionally, acetaldehyde-treated oligonucleotides were efficient in preventing digestion by the exonuclease function of T4 DNA polymerase compared to non-treated oligonucleotides, suggesting structural distortions of DNA caused by acetaldehyde-treatment. Neither in vitro DNA synthesis reactions of phi29 DNA polymerase nor in vitro RNA synthesis reactions of T7 RNA polymerase were observed when acetaldehyde-treated plasmid DNA was used, compared to when non-treated plasmid DNA was used, suggesting that acetaldehyde-induced DNA lesions inhibited replication and transcription in DNA metabolism.
Acetaldehyde-induced DNA lesions could affect the relative resistance to endo- and exo-nucleolytic activity and also inhibit in vitro replication and in vitro transcription. Thus, investigating the effects of acetaldehyde-induced DNA lesions may enable a better understanding of the toxicity and carcinogenicity of acetaldehyde.
乙醛在接触酒精、香烟烟雾、污染空气和糖时产生，是一种高反应性化合物，对人类具有致癌性，并在活的人类细胞中引起多种DNA损伤。此前，我们报道乙醛与寡核苷酸上相邻的脱氧鸟苷残基反应，但不与单个脱氧鸟苷残基或其他脱氧腺苷、脱氧胞嘧啶或胸腺嘧啶残基反应，并揭示其与dGpdG序列（GG二聚体）形成可逆的链内交联。
在这里，我们表明识别GG序列的限制性内切酶能够以低但显著的效率消化经乙醛处理的质粒DNA，而识别其他序列的限制性内切酶能够消化此类DNA。这表明乙醛在质粒DNA中产生了GG二聚体。此外，与未处理的寡核苷酸相比，经乙醛处理的寡核苷酸在防止T4 DNA聚合酶的核酸外切酶功能消化方面更有效，这表明乙醛处理导致了DNA的结构扭曲。与使用未处理的质粒DNA时相比，当使用经乙醛处理的质粒DNA时，未观察到phi29 DNA聚合酶的体外DNA合成反应或T7 RNA聚合酶的体外RNA合成反应，这表明乙醛诱导的DNA损伤抑制了DNA代谢中的复制和转录。
乙醛诱导的DNA损伤可能影响对内切和外切核酸酶活性的相对抗性，并且还抑制体外复制和体外转录。因此，研究乙醛诱导的DNA损伤的影响可能有助于更好地理解乙醛的毒性和致癌性。
