Mobile introns and homing endonuclease genes in the mitochondrial genomes of fungi.

真菌线粒体基因组中的移动内含子和归巢核酸内切酶基因。

• 批准号: RGPIN-2015-06658
• 负责人: Hausner, Georg
• 金额: $ 2.77万
• 依托单位: University of Manitoba
• 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=653229
• 关键词: Mobile; introns; homing; endonuclease; genes

Blue-stain fungi such as species of Ophiostoma, Grosmannia and Ceratocystis are vectored by insects and are of economic concerns as they discolour lumber, thus reducing the economic value of the wood. These fungi are also referred to as ophiostomatoid fungi and this group includes tree pathogens such as the causative agents of Dutch Elm Disease or Oak wilt. This research program in part focuses on the taxonomy and evolution of blue-stain fungi. Characterizing mitochondrial genomes of blue-stain fungi is part of the long term objectives of this proposal. These fungi are obligate aerobes thus functional mitochondrial are of upmost importance to these organisms in order to be competitive in their natural surroundings. The more immediate goals are to understand the origin and persistence of mobile genetic elements within fungal mitochondrial genomes (mtDNA) and to examine the implications these elements have on mtDNA stability and potentially on the virulence of these tree pathogens. This proposal will focus on characterizing the mitochondrial genomes of Ophiostoma ulmi and related species such as O. novo-ulmi, O. himal-ulmi and species related to the Ophiostoma piceae complex. The relative low cost and speed of next generation sequencing allows for sequencing of about 100 mtDNAs from various representatives of the ophiostomatoid fungi, comparative analysis of the resulting data should provide a resource for possible identifying inter-specific markers for identification of these economically important fungi. Also comparing the mtDNA of closely related species should reveal the impact of mobile elements such as group I and group II introns on mtDNA genome evolution. In addition these mobile elements sometimes encode DNA cutting enzymes, so called homing endonucleases. These enzymes have application in genomics and biotechnology. Homing endonucleases are currently employed in genome editing applications that involved gene replacement, mutagenesis and gene therapy. The proposed study will search for and biochemically analyze homing endonucleases and try to resolve their native DNA target sites and their relationships to each other and other mtDNA mobile elements. Finally this program will study in more detail a homing endonuclease gene that contains an intron. The long term goal is to develop a regulatory switch that permits in vivo regulation of homing endonuclease expression by manipulating intron splicing. It has been suggested that the in vivo control of homing endonuclease activity would allow for more precise timing of the inactivation or modification of genes.

蓝变真菌，如Ophiostoma，Grosmannia和Ceratocystis的物种是由昆虫传播的，并且由于它们使木材变色，从而降低了木材的经济价值，因此具有经济意义。这些真菌也被称为蛇口类真菌（ophiostomatoid fungi），这一组包括树木病原体，例如荷兰榆树病（Dutch Elm Disease）或橡树枯萎病（Oak wilt）的病原体。该研究计划部分集中在蓝变真菌的分类和进化。蓝变真菌的线粒体基因组特征是该提案的长期目标的一部分。这些真菌是专性需氧菌，因此功能性线粒体对这些生物体至关重要，以便在其自然环境中具有竞争力。 更直接的目标是了解真菌线粒体基因组（mtDNA）中移动的遗传元件的起源和持久性，并研究这些元件对mtDNA稳定性的影响，并可能对这些树木病原体的毒力。本研究将重点研究榆Ophiostoma ulmi及其相关物种的线粒体基因组。novo-ulmi、新乌木O. himal-ulmi和与Ophiostoma piceae复合体相关的物种。下一代测序的相对低的成本和速度允许从各种代表的ophiostomatoid真菌的约100个mtDNA的测序，所得到的数据的比较分析应该提供一个资源，为可能的识别种间标记，用于识别这些经济上重要的真菌。此外，比较密切相关的物种的mtDNA应该揭示移动的元素，如第I组和第II组内含子对mtDNA基因组进化的影响。此外，这些移动的元件有时编码DNA切割酶，所谓的归巢核酸内切酶。这些酶在基因组学和生物技术中具有应用。归巢核酸内切酶目前用于涉及基因置换、诱变和基因治疗的基因组编辑应用中。本研究将寻找并生化分析归巢核酸内切酶，并试图解析它们的天然DNA靶位点及其相互关系和与其他mtDNA移动的元件的关系。最后，这个项目将更详细地研究一个含有内含子的归巢核酸内切酶基因。长期目标是开发一种调节开关，其允许通过操纵内含子剪接在体内调节归巢核酸内切酶表达。已经提出，归巢核酸内切酶活性的体内控制将允许基因的失活或修饰的更精确定时。