The cross-regulation of host DNA replication and LTR Retrotransposons

宿主DNA复制和LTR反转录转座子的交叉调节

• 批准号: 8693413
• 负责人: MIGUEL ANGEL ZARATIEGUI BIURRUN
• 金额: $ 28.17万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-05 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8693413
• 关键词: Accounting; Address; Affect; Binding; Binding Sites; Biological Assay; Biology; Cell Cycle; Cell Cycle Stage; Cell physiology; Chromatin; Chromosome abnormality; Collaborations; DNA Binding; DNA Transposable Elements; DNA biosynthesis; DNA replication fork; DNA-Binding Proteins; Deposition; Disease; Elements; Employee Strikes; Epigenetic Process; Evolution; Fission Yeast; G2 Phase; Genetic; Genetic Recombination; Genome; Genome Stability; Genomic Instability; Genomics; Goals; Gypsies; Health; Heterochromatin; Homing; In Vitro; Investigation; Lead; Learning; Long Terminal Repeats; Malignant Neoplasms; Mediating; Mobile Genetic Elements; Modeling; Molecular; Nucleosomes; Parasites; Pathway interactions; Play; Positioning Attribute; Process; RNA Interference; Recruitment Activity; Regulation; Retroelements; Retrotransposon; Retroviridae; Role; Side; Site; Structure; Testing; Trans-Activators; Yeasts; base; blocking factor; chromatin remodeling; epigenetic variation; homologous recombination; in vivo; mutant; novel; preference; promoter; public health relevance; repaired; success

DESCRIPTION (provided by applicant): LTR Retrotransposons are mobile genetic elements and major constituents of eukaryotic genomes, where they contribute to structural variation and epigenetic regulation. They are highly related to Retroviruses, and like all parasitic elements their evolutionary success depends on exploitation of critical cellular processes. Their activity can lead to chromosomal alterations that drive diseases like cancer. We have discovered that the LTR Retrotransposon Tf1 inserts near genomic replication fork barriers, and includes new replication fork barriers in its own genome. In this proposal we aim to characterize the interaction of LTR Retrotransposons and host DNA replication, and how it influences integration site selection, genome integrity and epigenetic transcriptional silencing. The overall HYPOTHESIS to be evaluated is that the replication fork is a point of cross-talk between the host and the LTR retrotransposon, by way of trans-acting factors that bind to the transposon insertion site and the LTR and control replication fork progression through chromatin remodeling. This results in managed Homologous Recombination and transcriptional silencing. We will use the LTR Retrotransposons of the fission yeast Schizosaccharomyces pombe as models for the involvement of DNA replication in LTR Retrotransposon biology. Specific aims: 1. To determine the mechanism of Tf1 insertion site selection and to ascertain the role of Sap1 in this process. Sap1 is a DNA binding factor that blocks progression of the replication fork and guides insertion of Tf1 to the blocked sites. We wil characterize the involvement of the replication fork in the insertion pathway and the possible tethering role of Sap1 in the homing mechanism. 2. To determine the influence of Retrotransposons on DNA replication and their consequences on DNA replication directionality and genome stability. The LTR are notoriously recombinogenic but the reasons are unknown. We will investigate the involvement of the replication fork barriers present in LTR in their recombinogenic potential, and their consequences on genome instability and the phenomenon of directional replication. 3. To determine the mechanism of transcriptional silencing of LTR retrotransposons, and the interaction between DNA replication and RNAi. Heterochromatic silencing is a universal feature of Transposable Elements. We have discovered the same factors that manage replication fork progression at the LTR determine a novel repressive heterochromatin structure that silences it. We will investigate the involvement of the DNA replication management factors on the mechanisms of transcriptional silencing of LTR retrotransposons. Significance: These studies will provide a novel and comprehensive model of host-retroelement interactions, and their consequences on genome regulation and stability.

描述（由申请人提供）： LTR返回座子是移动遗传元素和真核基因组的主要成分，它们有助于结构变异和表观遗传调节。它们与逆转录病毒高度相关，并且像所有寄生元素一样，它们的进化成功取决于对关键细胞过程的开发。它们的活性会导致染色体改变，从而驱动癌症等疾病。我们已经发现，LTR逆转座子TF1在基因组复制叉附近插入，并在其自身的基因组中包括新的复制叉屏障。在此提案中，我们旨在表征LTR逆转录子和宿主DNA复制的相互作用，以及它如何影响整合位点选择，基因组完整性和表观遗传转录沉默。要评估的总体假设是，复制叉是宿主和LTR逆转录子之间的串扰，这是通过与跨座子插入位点结合的反式作用因子以及LTR和控制复制的方式 分叉通过染色质重塑进行进展。这导致管理的同源重组和转录沉默。我们将使用裂变酵母裂菌酵母POMBE的LTR逆转录子作为DNA复制参与LTR Retrotransposon生物学的模型。具体目的：1。确定TF1插入位点选择的机制并确定SAP1在此过程中的作用。 SAP1是DNA结合因子 阻止复制叉的进展，并指导将TF1插入到阻塞位点。我们将表征复制叉在插入途径中的参与以及SAP1在归巢机制中的束缚作用。 2。确定逆转录子对DNA复制的影响及其对DNA复制方向性和基因组稳定性的影响。 LTR众所周知是重组的，但原因尚不清楚。我们将研究LTR中存在的复制叉屏障的重组潜力，以及它们对基因组不稳定性的后果和定向复制现象的影响。 3。确定LTR逆转录子的转录沉默的机理，以及DNA复制与RNAi之间的相互作用。杂色沉默是转座元素的通用特征。我们发现了在LTR处管理复制叉进展的相同因素决定了一种沉默的抑制性异染色质结构。我们将研究DNA复制管理因子关于LTR返回转座子的转录沉默机制的参与。意义：这些研究将提供一种新颖而全面的宿主 - 返回相互作用模型，以及它们对基因组调节和稳定性的影响。