Regulation of Sexual Differentiation in Malaria Parasites

好了！ 项目摘要/摘要 疟疾是世界上发病率和死亡率最高的蚊媒疾病。之后 在过去的二十年里，疟疾发病率和死亡率显著下降，而在过去的几年里，疟疾的发病率和死亡率则趋于平稳。 五年来，突显了进一步干预的必要性。疟疾传播需要寄生虫 从复制的无性血液阶段分化为非复制的雄配子体和雌配子体 感染蚊子所必需的。配子体发育的早期阶段是一个关键时期 寄生虫不仅需要启动配子体特有的转录程序，还必须阻止 与无性复制相关的导致细胞周期进入的基因的表达。我们的长期目标是 通过干扰调节机制来阻断疟疾寄生虫的传播和复制 在寄生虫生命周期中管理这一重要的控制点。最近的研究报告说，特定的上调 性交寄生虫中的染色质修饰酶，表明染色质重组起作用 在无性生殖向配子体转变过程中起着至关重要的作用。虽然技术障碍阻碍了学习 配子体发育的这些关键早期阶段的染色质组织和基因表达 最近发表的一项研究发现，在更多的人中，亚端粒异染色质结构域的特异性扩展 成熟配子体。这一提议旨在检验寄生虫染色质重组的假设 有性行为的寄生虫和早期配子体中的景观对于从 无性复制形成可传播的形式。新方法，包括单细胞 转录学和细胞类型特异性染色质分析，现在允许研究人员定义基因表达和 首次发现配子体发育早期的染色质组织(目标1)，并研究了核染色质的功能 在配子体发育过程中，对染色质的调节至关重要的基因。Aim 2的实验 将确定可能的组蛋白去甲基酶在配子体发育中的关键作用。而这些酶 对于体外的无性生长来说，它们似乎都是可有可无的，它们在配子体中显著上调，并且 早期配子细胞对这些酶的抑制剂高度敏感，敏感性在 配子体和第一阶段配子体。最后，目标3侧重于定义一种新发现的DNA的作用- 异染色质介导配子体发育过程中基因沉默的结合蛋白。初步 实验表明，表达缺失会导致配子体发育异常，上调 异染色质沉默的基因，以及染色质组织的变化。拟议中的实验将 为了解配子体发育的关键早期阶段提供了第一个窗口，并为 传输阻断策略。 好了！

! PROJECT SUMMARY/ABSTRACT Malaria is the mosquito-borne disease responsible for the greatest morbidity and mortality world-wide. After significant reductions over the past two decades, malaria incidence and mortality have plateaued over the last five years highlighting the need for additional interventions. Malaria transmission requires parasites to differentiate from the replicating asexual blood stages to non-replicating male and female gametocytes necessary to infect mosquitos. The early stages of gametocyte development are a key period during which parasites not only need to initiate the gametocyte-specific transcriptional program, but must also block expression of genes that lead to cell-cycle entry associated with asexual replication. Our long-term goal is to block transmission and replication of malaria parasites by interfering with the regulatory mechanisms that govern this essential point of control in the parasite lifecycle. Recent studies reported specific up-regulation of chromatin-modifying enzymes in sexually committed parasites, suggesting that chromatin re-organization plays a crucial role during the asexual to gametocyte transition. While technical barriers have thwarted studying chromatin organization and gene expression in these critical early stages of gametocyte development, a recently published study observed specific expansion of subtelomeric heterochromatin domains in more mature gametocytes. This proposal aims to test the hypothesis that restructuring of the parasite chromatin landscape in sexually committed parasites and early gametocytes is critical for the developmental switch from asexual replication to the formation of transmissible forms. New approaches, including single-cell transcriptomics and cell-type specific chromatin analysis, now allow researchers to define gene expression and chromatin organization during early gametocyte development for the first time (Aim 1) and study the function of genes critical for regulation of chromatin specifically during gametocyte development. Experiments in Aim 2 will define the critical role of putative histone demethylases in gametocyte development. While these enzymes appear individually dispensable for asexual growth in vitro, they are notably upregulated in gametocytes, and early gametocytes are highly susceptible to inhibitors of these enzymes, with susceptibility peaking in gametorings and Stage I gametocytes. Lastly, Aim 3 focuses on defining the role of a newly identified DNA- binding protein in heterochromatin mediated gene-silencing during gametocyte development. Preliminary experiments show that loss of expression results in aberrant gametocyte development, upregulation of heterochromatin-silenced genes, and alterations in chromatin organization. The proposed experiments will offer a first window into the critical early stages of gametocyte development and provide new targets for transmission blocking strategies. !