CAREER: Characterizing molecular mechanisms that drive life cycle transitions in the African trypanosome

该项目的目的是了解寄生虫在生物体之间移动时如何适应不同的环境。非洲锥虫就是这样一种寄生虫的一个例子，它在受感染动物的血液和采采蝇之间移动。当采采蝇叮咬人类或有蹄动物时，寄生虫会转移到血液中，引起一种称为非洲锥虫病（昏睡病）的致命疾病。了解寄生虫如何适应每种环境对于了解疾病流行地区的感染动态非常重要。此外，由于非洲锥虫很早就从其他研究充分的模式生物中分化出来，因此了解寄生虫适应不同环境时发生的基因调控将有助于了解基因调控系统是如何进化的。在研究实验室环境中对寄生虫适应的研究将为第一代高中生和在STEM领域代表性不足的大学一年级学生提供机会，与研究导师建立密切联系，这对该领域的保留很重要。学生还将有机会在课堂实验室环境中进行寄生虫适应性的开放式项目，理想情况下，增加他们加入研究实验室的信心和兴趣。布鲁氏菌）基因组被组织成功能不相关基因的大的多顺反子转录单位。没有DNA序列特异性转录因子已被确定，也没有明显的启动子序列。组蛋白修饰也与其他真核生物有很大不同。T.布氏杆菌的发现使一些人推测它们拥有组蛋白密码的“原始”版本。尽管存在这些差异，但需要大量的转录组重编程来促进在寄生虫在采采蝇载体和受感染哺乳动物的血流之间循环时发生的形态和代谢的巨大变化。驱动转录组中这些大规模变化的分子机制知之甚少。该研究项目的前提是，染色质相互作用的布罗莫结构域蛋白作为关键调节剂的转录组重编程寄生虫适应新的主机。该前提将通过以下来研究：1）使用RNA-seq确定溴结构域蛋白是否是维持昆虫阶段寄生虫中的中肠转录组所需的，2）使用CUT RUN表征在寄生虫从血流适应到昆虫阶段期间发生的溴结构域蛋白占据的变化&，和（3）当寄生虫从血流过渡到昆虫阶段时，确定邻近动态布罗莫结构域蛋白占据区域的候选基因的敲低表型。这一知识有望突出真核生物中基因调控的差异，这些差异早期与更好研究的模型系统不同。该奖项由综合有机体系统部的共生、感染和免疫计划共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The purpose of this project is to understand how parasites adapt to different environments as they move between organisms. The African trypanosome is an example of one such parasite that moves between the blood of infected animals and the tsetse fly. When a tsetse fly bites a human or a hooved animal, parasites are transferred to the bloodstream and cause a fatal disease called African trypanosomiasis (sleeping sickness). Understanding how the parasites adapt to each environment is important for understanding the dynamics of infection in regions where the disease is endemic. In addition, because African trypanosomes diverged very early from other well studied model organisms, understanding the gene regulation that occurs as parasites adapt to different environments will shed light on how gene regulatory systems evolved. The study of parasite adaptation in a research lab setting will provide opportunities for first- generation high school students and first year college students underrepresented in STEM fields to forge close connections with a research mentor, which is important for retention in the field. Students will also be given the opportunity to pursue open ended projects on parasite adaptation in a classroom laboratory setting, ideally increasing their confidence and interest in joining a research lab.The trypanosome (T. brucei) genome is organized into large polycistronic transcription units of functionally unrelated genes. No DNA sequence-specific transcription factors have been identified, nor are there obvious promoter sequences. Histone modifications also differ substantially from other eukaryotes. The lack of sequence specific transcription factors in T. brucei have led some to hypothesize that they harbor a ‘primitive’ version of the histone code. Despite these differences, substantial transcriptome reprogramming is required to facilitate the huge changes in morphology and metabolism that occur as parasites cycle between the tsetse fly vector and the bloodstream of infected mammals. The molecular mechanisms that drive these large- scale changes in the transcriptome are poorly understood. The premise of this research project is that chromatin interacting bromodomain proteins act as key modulators of transcriptome reprogramming in parasites adapting to a new host. This premise will be investigated by 1) determining whether bromodomain proteins are required for maintenance of the midgut transcriptome in insect-stage parasites using RNA-seq, 2) characterizing the changes in bromodomain protein occupancy that occur during parasite adaptation from the bloodstream to the insect stage using CUT&RUN, and (3) determining the knockdown phenotype of candidate genes proximal to areas of dynamic bromodomain protein occupancy as parasites transition from the bloodstream to the insect stage. This knowledge is expected to highlight differences in gene regulation in a eukaryote that diverged early from better studied model systems.This award was cofunded by the Symbiosis, Infection and Immunity Program in the Division of Integrative Organismal Systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.