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）：尽管遗传信息的稳定性是中心的，但基因组令人惊讶地不稳定。可转移的元素，即可以在许多非同源位置之间移动的离散DNA片段，在几乎所有生物体中都发现了广泛的元素。实际上，在某些基因组中，转座元序列是主要成分：令人惊讶的是，大约45％的人类基因组由可转座元序列组成。可转座元件运动的后果很多：插入可以导致宿主基因表达的改变，在元素编码的确定元素与宿主DNA的共价键中，例如，抗生素耐药性确定性与可以在细胞之间移动或逆转录病毒DNA在宿主基因组中移动的质粒的质粒连接在一起。同样，供体DNA切除后的供体DNA中的间隙通常不会恢复到其前盆地状态。此外，DNA断裂会导致DNA损伤信号。我们建议在分子和生物化学水平上研究转座的宿主如何控制转座，以及宿主如何对转座元件的运动做出反应，这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和酿酒酵母和果蝇中的昆虫转座子爱马仕。我们将探测复合物中特定核蛋白的组装如何通过在体外解剖TN7转座中控制换位，并通过分离和表征改变转置的宿主突变体来剖析宿主功能在TN7换位中的作用。我们还将探测爱马仕在酵母中的换位，并通过隔离变化其运动的突变体的射击。我们还将研究转座酶介导的断裂如何导致染色体重排，即遗传不稳定性。