RagA和Nprl2在果蝇肠道发育中的调节作用关系

The regulatory relationship between RagA and Nprl2 in Drosophila gut development

摘要:

动物胃肠道是食物消化和营养吸收器官，对机体健康至关重要。果蝇与哺乳动物的肠道在细胞组成、遗传调控等方面高度相似，是研究肠道发育的良好模型。体外培养细胞中的研究发现，Nprl2通过作用于Rag GTPase，抑制雷帕霉素靶点复合物1 (target of rapamycin complex 1, TORC1)的活性，参与细胞代谢的调节。前期报道nprl2突变果蝇具有前胃增大、消化能力降低等肠道衰老相关表型。但对于Nprl2是否通过Rag GTPase调控肠道发育等方面尚不清楚。为了探究Rag GTPase在Nprl2调控果蝇肠道发育中的作用，本研究利用遗传杂交结合免疫荧光等方法对RagA敲减和nprl2突变果蝇的肠道形态、肠道细胞组成等方面进行研究。发现单独敲减RagA可以引起肠变粗、前胃增大等表型，敲减RagA能挽救nprl2突变体中肠道变细、分泌型细胞减少的表型，但并不能挽救nprl2突变体中前胃增大的表型。以上结果表明，RagA在肠道发育中发挥重要作用，Nprl2通过作用于Rag GTPase调节肠道细胞分化和肠道形态，但Nprl2对前胃发育和肠道的消化功能的调节可能通过不依赖于Rag GTPase的机制实现。

Abstract:

The gastrointestinal tract is the largest digestive organ and the largest immune organ and detoxification organ, which is vital to the health of the body. Drosophila is a classic model organism, and its gut is highly similar to mammalian gut in terms of cell composition and genetic regulation, therefore can be used as a good model for studying gut development. target of rapmaycin complex 1 (TORC1) is a key factor regulating cellular metabolism. Nprl2 inhibits TORC1 activity by reducing Rag GTPase activity. Previous studies have found that nprl2 mutated Drosophila showed aging-related phenotypes such as enlarged foregastric and reduced lifespan, which were caused by over-activation of TORC1. In order to explore the role of Rag GTPase in the developmental defects of the gut of nprl2 mutated Drosophila, we used genetic hybridization combined with immunofluorescence to study the intestinal morphology and intestinal cell composition of RagA knockdown and nprl2 mutated Drosophila. The results showed that RagA knockdown alone could induce intestinal thickening and forestomach enlargement, suggesting that RagA also plays an important role in intestinal development. Knockdown of RagA rescued the phenotype of intestinal thinning and decreased secretory cells in nprl2 mutants, suggesting that Nprl2 may regulate the differentiation and morphology of intestinal cells by acting on RagA. Knockdown of RagA did not rescue the enlarged forestomach phenotype in nprl2 mutants, suggesting that Nprl2 may regulate forestomach development and intestinal digestive function through a mechanism independent of Rag GTPase.