Epigenetic control of mammalian retrotransposons

哺乳动物逆转录转座子的表观遗传控制

• 批准号: 7064495
• 负责人: Michael Lee
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7064495
• 关键词: DNA methylation; chromatin; computational biology; gene expression; genetic models; genetic regulation; genetic transcription; human tissue; molecular genetics; nucleic acid sequence; serial analysis of gene expression; tissue /cell culture; transfection /expression vector; transposon /insertion element

My group has established an experimental system to study epigenetic control of L1 retrotransposon reporters integrated de novo into human or mouse chromosomes. Using this tissue culture system, we are studying the mechanism of variegation and silencing of L1 reporters, newly inserted via a retrotransposition-dependent mechanism. We have also studied epigenetic control of L1 retrotransposons in situ in the human and mouse genomes, and the relationship between such control and L1 expression in various cells. These experiments, as a test of the "genome defense model", have shown that DNA methylation does not by itself account for exceptionally strong negative regulation of L1 transcription in somatic tissues.We have successfully sequenced and analyzed several full Serial Analysis of Gene Expression (SAGE) long-tag libraries to characterize global transcript levels, including those corresponding to repetitive and transposable elements, in somatic cells with altered epigenetic controls. The libraries completed to date include numerous transcripts that are differentially expressed at very high ratios. We are now identifying the differentially expressed transcripts and further characterizing how altered expression may be related to changed epigenetic control.

我的小组已经建立了一个实验系统，研究L1逆转录转座子报告基因从头整合到人类或小鼠染色体的表观遗传控制。使用这种组织培养系统，我们正在研究杂色和沉默的L1报告，新插入通过逆转录依赖的机制的机制。我们还研究了人类和小鼠基因组中原位L1反转录转座子的表观遗传控制，以及这种控制与各种细胞中L1表达之间的关系。这些实验，作为“基因组防御模型”的测试，已经表明DNA甲基化本身并不能解释体细胞组织中L1转录异常强烈的负调控。我们已经成功地测序和分析了几个完整的基因表达系列分析（SAGE）长标签文库，以表征全局转录水平，包括那些对应于重复和转座元件的转录水平，在改变了表观遗传控制的体细胞中。迄今为止完成的文库包括许多以非常高的比率差异表达的转录本。我们现在正在鉴定差异表达的转录本，并进一步表征表达的改变如何与表观遗传控制的改变相关。