Ngamphiw Chumpol, Tongsima Sissades, Mutirangura Apiwat
Inter-Department Program of Biomedical Sciences, Faculty of Graduate School, Chulalongkorn University, Bangkok, Thailand; Genome Technology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand.
Genome Technology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand.
PLoS One. 2014 Nov 19;9(11):e113434. doi: 10.1371/journal.pone.0113434. eCollection 2014.
Long INterspersed Element-1 (LINE-1 or L1) is a retrotransposable element that has shaped the evolution of mammalian genomes. There is increasing evidence that transcriptionally active L1 could have been co-opted through evolution to play various roles including X-inactivation, homologous recombination and gene regulation. Here, we compare putatively active L1 distributions in the mouse with human. L1 density is higher in the mouse except for the Y-chromosome. L1 density is the highest in X-chromosome, implying an X-inactivation role. L1 is more common outside genes (intergenic) except for the Y-chromosome in both species. The structure of mouse L1 is distinguished from human L1 by the presence of a 200 bp repeat in the 5' UTR of the former. We found that mouse intragenic L1 has significantly higher repeat copy numbers than intergenic L1, suggesting that this is important for control of L1 expression. Furthermore, a significant association between the presence of intragenic L1s and down-regulated genes in early embryogenesis was found in both species. In conclusion, the distribution of L1 in the mouse genome points to biological roles of L1 in mouse similar to human.
长散在核元件1（LINE-1或L1）是一种反转录转座元件，它塑造了哺乳动物基因组的进化。越来越多的证据表明，转录活跃的L1可能在进化过程中被征用以发挥各种作用，包括X染色体失活、同源重组和基因调控。在这里，我们比较了小鼠和人类中假定活跃的L1分布。除Y染色体外，小鼠中的L1密度更高。L1密度在X染色体中最高，这意味着它具有X染色体失活的作用。在这两个物种中，除Y染色体外，L1在基因外（基因间）更为常见。小鼠L1的结构与人类L1的区别在于前者的5'非翻译区存在一个200 bp的重复序列。我们发现，小鼠基因内L1的重复拷贝数明显高于基因间L1，这表明这对L1表达的控制很重要。此外，在这两个物种的早期胚胎发育中，基因内L1的存在与下调基因之间都存在显著关联。总之，L1在小鼠基因组中的分布表明L1在小鼠中具有与人类相似的生物学作用。
