弓形虫DNA甲基转移酶在速/缓殖子相互转化过程中的作用机制研究

弓形虫是一种重要的胞内寄生原虫，全球约有1/3人口为血清学阳性。我组曾报道弓形虫DNA CpG甲基化的基因可能与弓形虫组蛋白乙酰化和能量代谢有关，进而参与了弓形虫速-缓殖子的相互转化。我们构建了弓形虫甲基转移酶（DNMTa或DNMTb）敲除的ME49虫株，发现在无葡萄糖培养基中敲除株的增殖变慢以及TgDNMT与烯醇酶（ENO)互作，说明弓形虫DNMT与代谢有关；且代谢组学检测说明DNMTb敲除可抑制弓形虫的糖酵解。敲除DNMTa可抑制其向缓殖子转化，敲除DNMTb则促进其转化。我们拟通过检测ME49、单敲或双敲除DNMTa和DNMTb的各虫株的转录组、代谢组、及特定基因组蛋白乙酰化，验证弓形虫DNMT可能通过调控重要的代谢酶活性来调节代谢通路和能量代谢，或通过调节组蛋白乙酰化来调控弓形虫速、缓殖子的相互转化。研究弓形虫速、缓殖子之间的相互转化机制对弓形虫的防治与致病机制研究具有重要意义。

Toxoplasma gondii is an important intracellular protozoan. About one-third of the world's population is seropositive. Our group has reported that the DNA CpG methylated genes of Toxoplasma gondii may be related to histone acetylation and energy metabolism, and may be involved in the transformation between the tachyzoites and bradyzoites. We constructed the DNA methyltransferase (DNMTa or DNMTb) knockout strains of ME49. We found that the growth of the knockout strains was slowed down in glucose-free culture, and the interaction between TgDNMT and enolase (ENO), which indicated that DNMT was related to parasite energy metabolism. Metabonomics detection showed that DNMTb knockout could inhibit the glycolysis of Toxoplasma gondii tachyzoites, DNMTa knockout could inhibit the transformation of tachyzoites to bradyzoites, while DNMTb knockout could promote this transformation. Through detecting the transcriptomes, metabolomes, histone acetylation of the specific genes of ME49, ME49-ΔDNMTa, ME49-ΔDNMTb, and ME49-ΔDNMTa/b, we intend to verify that TgDNMT may regulate the parasite's metabolic pathways and energy metabolism by regulating the activity of the important metabolic enzymes, or by regulating histone acetylation, and eventually to regulate the inter-conversion of Toxoplasma tachyzoites and bradyzoites,. It is of great significance to study the transformation mechanism between T.gondii tachyzoites and bradyzoites, for the prevention and treatment and the researches of Toxoplasma gondii pathogenesis.