Nair Sindhu G, Loppnow Glen R
Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
ACS Omega. 2019 Feb 28;4(2):3469-3475. doi: 10.1021/acsomega.8b03017. Epub 2019 Feb 15.
It has been well established that mutations in K- and N- proto-oncogenes can convert them into active oncogenes. Current molecular cancer research has been focused on determining the key steps by which cellular genes become oncogenes and not on the underlying and fundamental chemical damage mechanism and susceptibility to damage. In this study, we investigate the damage hot spots present in the N- and K- genes upon exposure to UVC radiation. Detection of damage is accomplished by a simple, sensitive, mix-and-read assay using an EvaGreen probe in a 96-well microtiter plate. Our results show that, although there is high degree of sequential similarities among K- and N- genes, they show different degrees of UV damage in different portions of their genomes. Our experiments demonstrate that overall, the K- genome is more prone to UVC damage than the N- genome. We observe that the extent of damage increases with increasing number of TTs in a sequence, consistent with previous results that show that thymine cyclobutyl photodimers are the primary DNA damage photoproducts upon UVC irradiation. This understanding of the effect of UVC radiation on various codons of K- and N- genes will help to increase our understanding about hot spots of DNA damage and the chemical damage mechanism.
K-原癌基因和N-原癌基因中的突变可将它们转化为活性癌基因，这一点已得到充分证实。当前的分子癌症研究主要集中在确定细胞基因转变为癌基因的关键步骤，而不是潜在的基本化学损伤机制和对损伤的易感性。在本研究中，我们调查了N-基因和K-基因在暴露于紫外线C（UVC）辐射后出现的损伤热点。通过在96孔微量滴定板中使用EvaGreen探针进行简单、灵敏的混合读取测定来完成损伤检测。我们的结果表明，尽管K-基因和N-基因之间存在高度的序列相似性，但它们在基因组的不同部分表现出不同程度的紫外线损伤。我们的实验证明，总体而言，K-基因组比N-基因组更容易受到UVC损伤。我们观察到，损伤程度随着序列中TT数量的增加而增加，这与之前的结果一致，即胸腺嘧啶环丁烷光二聚体是UVC照射后主要的DNA损伤光产物。对UVC辐射对K-基因和N-基因各种密码子影响的这种理解将有助于增进我们对DNA损伤热点和化学损伤机制的认识。
