Epitranscriptomics in the AIDS-opportunistic pathogen Toxoplasma gondii

弓形虫是一种细胞内寄生虫，已感染多达三分之一的人口。病原体 可导致先天性出生缺陷和危及生命的机会性感染艾滋病毒/艾滋病。的复制型 一个阶段（速殖子）发展成为潜伏阶段（缓殖子），存在于大脑、心脏和骨骼肌内 组织，并且不受免疫力和目前批准的抗寄生虫药物的影响。组织囊肿引起 免疫功能低下患者的反复感染复发，造成艾滋病毒/艾滋病的慢性疾病 患者尽管它在临床上很重要，但我们对协调这一过程的分子细节知之甚少。 速殖子和缓殖子之间的转换。研究表明缓殖子的发育， 其可以在体外由细胞应激触发，是一个在转录水平受到调控的复杂过程。 和转录后水平。最近，在其他物种中已经表明，mRNA修饰， 特别是6位腺苷（m6 A）转录后甲基化，通过以下方式影响基因表达 改变RNA加工或翻译。m6 A标记的变化与调节细胞凋亡有关。 压力、发育和分化。m6 A的发现代表了基因调控的新层面 这被称为表观转录组学，还没有在原生动物寄生虫中进行过研究。在初步研究中，我们 确定弓形虫RNA受m6 A影响，我们已经开始表征 传递这种RNA修饰。在艾滋病毒/艾滋病的背景下，弓形虫中m6 A的研究具有重要意义， 这种修饰与细胞中应激诱导的变化有关，因此m6 A很可能是 参与缓殖子发育。在这个新的R21，我们将解决我们的假设，m6 A mRNA 通过鉴定m6 A的变化，速殖子分化为缓殖子需要修饰 阶段转换期间的表位转录组（目的1），并确定“作家”蛋白复合物， m6 A到弓形虫mRNA上（Aim 2）。我们提出的研究将是第一次分析m6 A对mRNA的影响， 寄生虫，并将产生有价值的数据集和试剂，需要询问这个重要的新领域， 调查有关的发展组织囊肿，引起慢性弓形虫病， 艾滋病毒/艾滋病患者。

Toxoplasma gondii is an intracellular parasite that has infected up to one-third of the population. The pathogen can cause congenital birth defects and life-threatening opportunistic infection in HIV/AIDS. The replicative stage (tachyzoite) develops into a latent stage (bradyzoite) that resides inside brain, heart, and skeletal muscle tissues, and is impervious to immunity and currently approved antiparasitic drugs. Tissue cysts give rise to recurrent reactivation of infection in immunocompromised patients, creating chronic disease in HIV/AIDS patients. Despite its clinical importance, we know very little about the molecular details orchestrating the conversion between tachyzoites and bradyzoites. Studies have revealed that the development of bradyzoites, which can be triggered in vitro by cellular stress, is a complex process subject to regulation at transcriptional and post-transcriptional levels. Recently, it has been shown in other species that mRNA modifications, specifically post-transcriptional methylation of adenosines at position 6 (m6A), influence gene expression by altering RNA processing or translation. Changes in m6A marks have been associated with modulating cellular stress, development, and differentiation. The discovery of m6A represents a new layer of gene regulation called epitranscriptomics that has not been investigated in protozoan parasites. In preliminary studies, we establish that Toxoplasma RNA is subject to m6A, and we have begun characterizing the enzyme complex that delivers this RNA modification. The study of m6A in Toxoplasma in the context of HIV/AIDS is significant as this modification has been linked to stress-induced changes in cells, making it highly likely that m6A participates in bradyzoite development. In this new R21, we will address our hypothesis that m6A mRNA modifications are required for tachyzoite differentiation into bradyzoites by identifying changes in the m6A epitranscriptome during stage conversion (Aim 1) and determining the “writer” protein complex that delivers m6A onto Toxoplasma mRNA (Aim 2). Our proposed studies will be the first analysis of m6A on mRNA in parasites, and will generate valuable datasets and reagents needed to interrogate this vital new area of investigation relevant to the development of the tissue cysts, which give rise to chronic toxoplasmosis in HIV/AIDS patients.