Investigating the role of Retrotransposon muERV-L reactivation in Tumorigenesis

研究逆转录转座子 muERV-L 重新激活在肿瘤发生中的作用

• 批准号: 8832362
• 负责人: Andrew Joseph Modzelewski
• 金额: $ 5.24万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8832362
• 关键词: Adult; Base Sequence; Biochemical; Bioinformatics; Cancer Biology; Cancer Model; Cell Line; Cells; Characteristics; Clustered Regularly Interspaced Short Palindromic Repeats; Data; Defect; Development; Elements; Embryonic Development; Epigenetic Process; Event; Evolution; Family; FarGo; Gene Expression; Gene Expression Regulation; Gene Structure; Genes; Genetic; Genome; Genomic approach; Goals; High-Throughput Nucleotide Sequencing; Histocompatibility Testing; Human Genome; Investigation; Lead; Location; Long Terminal Repeats; Malignant Neoplasms; Malignant neoplasm of lung; Mediating; Modeling; Molecular; Mus; Nucleic acid sequencing; Organism; Pathology; Pattern; Pluripotent Stem Cells; Polyadenylation; Positioning Attribute; Procedures; Protein p53; Proviruses; Public Health; Regulation; Regulator Genes; Regulatory Element; Reporting; Research Design; Retrotransposition; Retrotransposon; Role; Sampling; Signal Transduction; Staging; Techniques; Time; Tissues; Tumor Suppressor Proteins; Tumorigenicity; Untranslated RNA; cancer type; derepression; design; differential expression; experience; genome editing; in vivo; induced pluripotent stem cell; insight; mouse genome; mouse model; mutant; novel; programs; promoter; public health relevance; tumor; tumor progression; tumorigenesis

 DESCRIPTION (provided by applicant): Investigating the role of Retrotransposon muERV-L reactivation in Tumorigenesis. Background: Throughout evolution, ancient foreign nucleic acid sequences have infected and spread throughout the genomes of nearly all organisms. These parasitic elements mobilize in order to rearrange their position and propagate throughout the host genome. 42% of the human genome originates from a class of mobile element called retrotransposons and has evolved elaborate mechanisms to suppress the potentially mutagenic effects of aberrant reactivations. Although exceedingly efficient at silencing retrotransposons, developmental and tissue specific expression patterns of specific retrotransposon families suggest that these elements have been domesticated by their host genomes. Preliminary results demonstrate that during the induction of pluripotent stem cells in the absence of the tumor suppressor p53, the ancient class of mouse retrotransposon, muERV-L is de-repressed while nearly all other retrotransposon silencing remains intact. This reactivation, occurring at thousands of loci, is accompanied by the significant misregulation of gene activity specifically adjacent to muERV-L loci. Whether these effects contribute to or are a consequence of the enhanced tumorigenicity of p53 loss is the focus of this investigation. Hypothesis: Our preliminary studies indicate that upon induction of pluripotent stem cells lacking the tumor suppressor p53, the retrotransposon muERV-L is reactivated with significant impact on neighboring gene activity. Therefore, I hypothesize that p53 mediates muERV-L retrotransposon silencing during tumor development. Specific Aims: (1) Rescue altered gene expression in p53 deficient iPS cells via muERV-L disruption. (2) Characterize aberrant retrotransposon activity in in vivo cancer development. (3) Investigate the mechanism through which p53 represses specific retrotransposons. Study design: The novel CRISPR genome editing technique pioneered here at UC Berkeley will be used to disrupt specific muERV-L loci to assess changes on potential cis regulatory effects. Next, two distinct mouse models of lung cancer will be used to investigate the in vivo effect of muERV-L reactivation on tumor formation. Genetic, biochemical and molecular approaches on p53 deficient cell lines and mouse models will be used to investigate the epigenetic and transcriptional machinery downstream of p53 that confer this sequence-specific regulation for retrotransposon silencing.

 描述(申请人提供)：研究反转录转座子MERV-L重新激活在肿瘤发生中的作用。背景：在整个进化过程中，古老的外源核酸序列感染并传播到几乎所有生物的基因组中。这些寄生元件为了重新排列它们的位置而移动，并在整个寄主基因组中传播。42%的人类基因组起源于一类称为反转录转座子的可移动元件，并进化出复杂的机制来抑制异常重新激活的潜在突变效应。虽然在沉默反转录转座子方面非常有效，但特定反转录转座子家族的发育和组织特异性表达模式表明，这些元件已经被它们的宿主基因组驯化。初步结果表明，在没有肿瘤抑制物p53的情况下，在诱导多能干细胞的过程中，小鼠古老的一类反转录转座子MuERV-L被去抑制，而几乎所有其他反转录转座子的沉默都保持不变。这种发生在数以千计的基因座上的重新激活，伴随着与MERV-L基因座毗邻的基因活性的严重错误调节。这些效应是否有助于或是P53缺失的致瘤性增强的结果是本研究的重点。假设：我们的初步研究表明，在缺乏肿瘤抑制基因p53的多能干细胞诱导后，反转录转座子MuERV-L被重新激活，并对邻近基因的活性产生显著影响。因此，我推测在肿瘤发生过程中，P53介导了逆转录病毒L反转录转座子沉默。具体目的：(1)通过阻断mERV-L基因，挽救p53基因缺失的iPS细胞中基因表达的改变。(2)体内肿瘤发生过程中反转座子活性异常的特征。(3)探讨P53抑制特定反转录转座子的机制。研究设计：加州大学伯克利分校首创的新型CRISPR基因组编辑技术将用于干扰特定的MuERV-L基因座，以评估潜在顺式调控效应的变化。接下来，我们将使用两种不同的小鼠肺癌模型来研究重组逆转录病毒L在体内对肿瘤形成的影响。利用遗传学、生物化学和分子生物学方法对p53基因缺陷的细胞系和小鼠模型进行研究，研究p53下游的表观遗传和转录机制，为反转录转座子沉默提供这种序列特异性调控。