Transposition of the Gnome MITE Family and its Development Toward a Gene Driver for Genetic Control of Mosquito-Borne Diseases

Gnome MITE 家族的转座及其向蚊媒疾病遗传控制基因驱动基因的发展

• 批准号: RGPIN-2014-04709
• 负责人: Yang, Guojun
• 金额: $ 1.52万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=669171
• 关键词: Transposition; Gnome; MITE; Family; its

Yellow fever mosquito is an important vector for pathogens of diseases such as Yellow Fever, Dengue Fever and Chikungunya. Large scale mosquito control is a challenging task. Genetic control of mosquitoes is promising and more environmentally friendly than chemical applications. One attractive approach is population replacement where a small number of mosquitoes resistant to pathogens can spread the resistance in a population, pushing the defense line beyond the disease vectors. The success of this approach relies on a gene drive system to spread the resistance.* Transposable elements (TEs), known as jumping genes, can increase their frequency in a population rapidly and are considered excellent candidates for a gene drive system. However, currently used TEs in the studies on the mosquito are from other species and typically remobilize inefficiently once they integrate into the chromosomes of the mosquito. Elements in mosquito that transpose and amplify efficiently are highly desirable. A group of TEs in plants and animals named miniature inverted repeat transposable elements (MITEs) bear these desirable features. Genome wide analyses of MITEs in the yellow fever mosquito in my lab identified its youngest and most likely active MITE family we named Gnome. However, this element does not carry the gene that produces the protein responsible for its mobilization. With major improvements of a computational tool name MITE Analysis Kit that I previously developed, an elusive single copy element we named Ozma was discovered to be the ancestral element of Gnome. Using an experimental system I previously established for rice elements, preliminary studies suggest that the Ozma transposase, protein that moves TEs, is capable of mobilizing Gnome in yeast.* Here I propose detailed studies on these elements to deepen our knowledge on the transposition mechanisms of Gnome and related elements, understand their current activity in mosquito and use them as genetic tools. To achieve these goals, we will perform the following studies: (1) Characterization of Gnome transposition and Ozma transposase to reveal important features; (2) Analyses of the activities of MITE families and their autonomous element in mosquito; (3) Development of MITE based cargo gene vectors and remobilization systems. We will use a combined approach of molecular biology and computational biology in these studies.* The proposed studies will reveal the secrets of the mechanisms underlying the transposition and amplification of the youngest MITE family in the mosquito genome. It will make important contributions to our knowledge on genome evolution. The elements we will analyze in these studies are potentially efficient novel genetic tools for scientific research and practical applications such as transgenesis, gene therapy and genetic control of pest insects. During the studies, highly qualified personnel including postdoctoral fellows, graduate students and undergraduate students will be trained in my lab. Therefore, the proposed research will not only generate new knowledge for the research community, but will also contribute to the Canadian economy in the areas of education, medicine and environment protection.

黄热病蚊子是黄热病、登革热和基孔肯雅热等疾病病原体的重要媒介。大规模的蚊虫控制是一项具有挑战性的任务。蚊子的遗传控制是有前途的，比化学应用更环保。一种有吸引力的方法是种群替换，其中少量对病原体具有抗性的蚊子可以在种群中传播抗性，从而将防线推到病媒之外。这种方法的成功依赖于基因驱动系统来传播抗性。 转座因子（Transposable elements，TE），又称跳跃基因（jumping gene），可以迅速增加它们在种群中的频率，被认为是基因驱动系统的优秀候选者。然而，目前在蚊子研究中使用的TE来自其他物种，并且一旦它们整合到蚊子的染色体中，通常不能有效地再动员。蚊子中有效转座和扩增的元件是高度期望的。在动植物中有一类被称为微型反向重复转座因子（miniature inverted repeat transposable elements，MITE）的转座因子具有这些特征。在我的实验室中，对黄热病蚊子中的MITE进行了全基因组分析，确定了它最年轻、最有可能活跃的MITE家族，我们将其命名为Gnome。然而，这个元件不携带产生负责其动员的蛋白质的基因。随着我以前开发的名为MITE分析工具包的计算工具的重大改进，我们命名为Ozma的难以捉摸的单拷贝元素被发现是Gnome的祖先元素。 使用我之前建立的水稻元素实验系统，初步研究表明，Ozma转座酶（移动TE的蛋白质）能够动员酵母中的Gnome。 在这里，我建议对这些元件进行详细的研究，以加深我们对Gnome和相关元件的转座机制的认识，了解它们在蚊子中的当前活动，并将它们作为遗传工具。为了实现这些目标，我们将进行以下研究：（1）Gnome转座和Ozma转座酶的表征以揭示重要特征;（2）MITE家族及其在蚊子中的自主元件的活性分析;（3）基于MITE的货物基因载体和再动员系统的开发。在这些研究中，我们将使用分子生物学和计算生物学相结合的方法。 拟议的研究将揭示蚊子基因组中最年轻的MITE家族的转座和扩增机制的秘密。它将对我们的基因组进化知识做出重要贡献。我们将在这些研究中分析的元素是潜在的有效的新的遗传工具，为科学研究和实际应用，如转基因，基因治疗和遗传控制的害虫。在研究期间，高素质的人才，包括博士后研究员，研究生和本科生将在我的实验室培养。因此，拟议的研究不仅将为研究界产生新的知识，而且还将在教育，医学和环境保护领域为加拿大经济做出贡献。