Transposition of Tn7 and Hermes

Tn7 和 Hermes 的转位

• 批准号: 7022089
• 负责人: NANCY Craig CRAIG
• 金额: $ 31.85万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7022089
• 关键词: DNA damage; DNA repair; Drosophilidae; Escherichia coli; RNA binding protein; RNA interference; Saccharomyces cerevisiae; arthropod genetics; cell line; chemical stability; endopeptidases; fungal genetics; fungal proteins; gene rearrangement; genetic regulation; genetic screening; host organism interaction; intermolecular interaction; microorganism culture; molecular assembly /self assembly; molecular chaperones; molecular genetics; nucleic acid denaturation; transposon /insertion element

DESCRIPTION (provided by applicant): Although the constancy of genetic information is central, genomes are surprisingly unstable. Transposable elements, i.e. discrete DNA segments that can move between many non-homologous positions, are widespread, having been found in virtually all organisms. Indeed, in some genomes, transposable element sequences are the predominant component: strikingly, about 45% of the human genome is composed of transposable element sequences. The consequences of transposable element movement are many: insertion can result in alterations in host gene expression, in the covalent linkage of element-encoded determinates to host DNA, for example the joining of antibiotic resistance determinants to plasmids that can move between cells or the integration of retroviral DNA into host genomes. Also, gaps in the donor DNA following element excision are often not restored to their pre- transposon state. Moreover, DNA breaks can result in DNA damage signals. We propose to study at the molecular and biochemical level how transposition is controlled by its host and how the host responds to the movement of transposable elements, a potentially lethal event because it involves DNA breakage and joining. We will study the bacterial transposon Tn7 in E. coli and the insect transposon Hermes in S. cerevisiae and in Drosophila. We will probe how the assembly of particular nucleoprotein in complexes can control transposition though in vitro dissection of Tn7 transposition and will dissect the role of host functions in Tn7 transposition through the isolation and characterization of host mutants that alter transposition. We will also probe Hermes transposition in yeast and flies through the isolation of mutants that alter its movement. We will also examine how the transposase-mediated breaks can lead to chromosomal rearrangements, i.e. genetic instability.

描述（由申请人提供）：虽然遗传信息的恒定性是核心，但基因组却出人意料地不稳定。转座元件，即可以在许多非同源位置之间移动的离散 DNA 片段，广泛存在于几乎所有生物体中。事实上，在一些基因组中，转座元件序列是主要组成部分：令人惊讶的是，人类基因组的约 45% 是由转座元件序列组成的。转座元件移动的后果有很多：插入可能导致宿主基因表达的改变、元件编码的决定簇与宿主DNA的共价连接的改变，例如抗生素抗性决定簇与可以在细胞之间移动的质粒的连接或整合将逆转录病毒DNA导入宿主基因组。此外，元件切除后供体 DNA 中的缺口通常不会恢复到转座子前的状态。此外，DNA 断裂会导致 DNA 损伤信号。我们建议在分子和生化水平上研究转座如何受宿主控制，以及宿主如何响应转座元件的运动，转座元件的运动是一个潜在的致命事件，因为它涉及 DNA 断裂和连接。我们将研究大肠杆菌中的细菌转座子 Tn7 以及酿酒酵母和果蝇中的昆虫转座子 Hermes。我们将探讨复合物中特定核蛋白的组装如何通过 Tn7 转座的体外解剖来控制转座，并将通过改变转座的宿主突变体的分离和表征来剖析宿主功能在 Tn7 转座中的作用。我们还将通过分离改变其运动的突变体来探究酵母和果蝇中的 Hermes 转座。我们还将研究转座酶介导的断裂如何导致染色体重排，即遗传不稳定。