Control of VSG pre-mRNA processing in infectious Trypanosoma brucei

感染性布氏锥虫 VSG 前 mRNA 加工的控制

• 批准号: 10685494
• 负责人: CHRISTIAN TSCHUDI
• 金额: $ 41.88万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-23 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10685494
• 关键词: 3' Splice Site; 3' Untranslated Regions; Africa South of the Sahara; African; African Trypanosomiasis; Antigenic Variation; Biology; Blood; Blood Circulation; Cattle; Cells; Chronic; Code; Communicable Diseases; Complex; Development; Disease; Dissection; Domestic Pig; Economic Development; Enhancers; Environment; Exposure to; Face; Genes; Genetic Enhancer Element; Genetic Transcription; Genome; Goals; Human; Immune Evasion; In Vitro; Infection; Insect Vectors; Instruction; Intercistronic Region; Investigation; Life; Life Cycle Stages; Livestock; Membrane Glycoproteins; Messenger RNA; Modeling; Molecular; Monitor; Output; Parasites; Pharmaceutical Preparations; Play; Polyadenylation Pathway; Population; Production; Proteins; Protozoa; Public Health; RNA Sequences; RNA Splicing; RNA-Binding Proteins; Regulation; Research; Resolution; Role; Salivary Glands; Site; Surface; System; Therapeutic; Time; Tissues; Trans-Activators; Trans-Splicing; Transcript; Trypanosoma; Trypanosoma brucei brucei; Tsetse Flies; Vaccines; Variant; combat; coping; feeding; inducible gene expression; insight; live cell imaging; mRNA Expression; mRNA Precursor; mRNA Stability; metacyclogenesis; nagana; news; novel; pathogen; polyadenylated messenger RNA; posttranscriptional; programs; side effect; single-cell RNA sequencing; time use; transmission process; vector; wasting

Project Summary This application focuses on the protozoan parasite Trypanosoma brucei, which is transmitted among mammalian hosts by tsetse-flies and, due to effective immune evasion, causes chronic and lethal infections, specifically African sleeping-sickness in humans and nagana in cattle. Whereas human African trypanosomiasis has been declining recently, livestock infections remain prevalent and have a profound effect on economic development in sub-Saharan Africa. There are no vaccines and therapeutic drugs have serious side effects and decreasing efficacy. Thus, there is a pressing need for research to better understand the biology of these pathogens and the mechanisms they use to survive within their hosts. T. brucei undergoes a complex life cycle between the mammalian host and the blood-feeding tsetse fly vector. To cope with the changing environment, the parasite transitions through distinct life cycle forms that have evolved to assure survival and successful transmission to the next host. For instance, when residing in the mammalian host, T. brucei expresses a variant surface glycoprotein (VSG) coat, which is the paradigm for antigenic variation. Although there are hundreds of VSG genes in the genome, bloodstream-form VSG expression is restricted to 1 of about 15 specialized telomeric bloodstream expression sites (BES). In the salivary glands of the insect vector metacyclic trypanosomes are covered by a specific and small subset of VSGs, the metacyclic VSGs (mVSGs), which enable transmission to a vertebrate host. mVSG expression is triggered by an unknown mechanism and in vitro can be achieved in the absence of tsetse tissues by induced expression of the RNA-binding protein 6 (RBP6). One major goal of this application will be to examine how trypanosomes receive instructions to begin synthesizing the mVSG coat, and when each cell begins expressing a single mVSG. We will use single-cell RNA-Seq and long-term live-cell imaging to answer mechanistic questions. In addition, our novel finding that mVSG genes encode an exonic splicing enhancer exposed a completely new aspect of VSG regulation and may explain the tightly-controlled extremely high output of mature mRNAs.

项目概要 本申请重点关注原生动物寄生虫布氏锥虫，该寄生虫在人群中传播 采采蝇作为哺乳动物宿主，由于有效的免疫逃避，导致慢性和致命的感染， 特别是人类的非洲昏睡病和牛的那加那病。而非洲人类锥虫病 最近，牲畜感染率有所下降，但牲畜感染仍然普遍，并对经济产生深远影响 撒哈拉以南非洲的发展。没有疫苗和治疗药物有严重的副作用 功效降低。因此，迫切需要进行研究以更好地了解这些物质的生物学特性。 病原体及其在宿主体内生存的机制。布氏锥虫经历了复杂的生命周期 哺乳动物宿主和吸血采采蝇媒介之间。为了应对不断变化的环境， 寄生虫通过不同的生命周期形式进行转变，这些形式的进化是为了确保生存和成功 传输到下一个主机。例如，当存在于哺乳动物宿主中时，T. brucei 表达 变异表面糖蛋白（VSG）外壳，这是抗原变异的范例。虽然有 基因组中有数百个 VSG 基因，血流形式的 VSG 表达仅限于约 15 个中的 1 个 专门的端粒血流表达位点（BES）。在昆虫媒介元循环的唾液腺中 锥虫由 VSG 的一个特定的小子集（元循环 VSG（mVSG））覆盖， 能够传输到脊椎动物宿主。 mVSG 表达由未知机制触发，并在 通过诱导表达 RNA 结合蛋白 6，可以在没有采采蝇组织的情况下实现体外实验 （RBP6）。该应用程序的一个主要目标是检查锥虫如何接收开始指令 合成 mVSG 外壳，以及当每个细胞开始表达单个 mVSG 时。我们将使用单细胞 RNA-Seq 和长期活细胞成像可回答机制问题。此外，我们的小说发现 mVSG 基因编码的外显子剪接增强子揭示了 VSG 调控的全新方面 可以解释成熟 mRNA 的严格控制极高的产量。