Department of Experimental Evolutionary Biology, University of Bologna, Bologna, Italy.
Cell Tissue Res. 2011 Dec;346(3):383-91. doi: 10.1007/s00441-011-1289-0. Epub 2011 Dec 10.
Long interspersed element-1s (LINE-1 or L1s) are abundant retrotransposons that occur in mammalian genomes and that can cause insertional mutagenesis and genomic instability. L1 activity is generally repressed in most cells and tissues but has been found in some embryonic cells and, in particular, in neural progenitors. Moreover, L1 retrotransposition can be induced by several DNA-damaging agents. We have carried out experiments to verify whether L1 retrotransposition is affected by oxidative DNA damage, which plays a role in a range of human diseases, including cancer and inflammatory and neurodegenerative disease. To this purpose, BE(2)C neuroblastoma cells, which are thought to represent embryonic precursors of sympathetic neurons, have been treated with hydrogen peroxide and subjected to an in vitro retrotransposition assay involving an episomal L1(RP) element tagged with enhanced green fluorescent protein. Our results indicate that hydrogen peroxide treatment induces an increase in the retrotransposition of transiently transfected L1(RP) and an increase in the expression of endogenous L1 transcripts. An increase of γ-H2AX foci and changes in the mRNA levels of MRE11, RAD50, NBN and ERCC1 (all involved in DNA repair) have also been found. Thus, oxidative stress can cause L1 dysregulation.
长散布元件-1 （LINE-1 或 L1s ）是大量存在于哺乳动物基因组中的逆转录转座子，可引起插入突变和基因组不稳定。L1 的活性通常在大多数细胞和组织中受到抑制，但在一些胚胎细胞中，特别是在神经祖细胞中发现了 L1 。此外，L1 逆转录转座可被几种 DNA 损伤剂诱导。我们进行了实验以验证 L1 逆转录转座是否受氧化 DNA 损伤的影响，氧化 DNA 损伤在包括癌症、炎症和神经退行性疾病在内的多种人类疾病中起作用。为此，用 H2O2 处理被认为代表交感神经元胚胎前体的 BE （ 2 ） C 神经母细胞瘤细胞，并进行了涉及带有增强型绿色荧光蛋白的外显子 L1 （ RP ）元件的体外逆转录转座测定。我们的结果表明，H2O2 处理诱导瞬时转染的 L1 （ RP ）的逆转录转座增加，并导致内源性 L1 转录本的表达增加。还发现 γ-H2AX 焦点增加以及 MRE11 、 RAD50 、 NBN 和 ERCC1 （均参与 DNA 修复）的 mRNA 水平变化。因此，氧化应激可导致 L1 失调。
