Evidence of tRNA cleavage in apicomplexan parasites: Half-tRNAs as new potential regulatory molecules of Toxoplasma gondii and Plasmodium berghei
Evidence of tRNA cleavage in apicomplexan parasites: Half-tRNAs as new potential regulatory molecules of Toxoplasma gondii and Plasmodium berghei
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DOI：
10.1016/j.molbiopara.2013.03.003
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发表时间：
2013-04-01
影响因子：
1.5
通讯作者：
Di Cristina, Manlio
中科院分区：
文献类型：
--
作者：
Galizi, Roberto;Spano, Furio;Di Cristina, Manlio
一些证据表明，从细菌到高等动物的生物体都具有一种受调节的内切核酸裂解途径，产生半tRNA片段。在本研究中，我们调查了这一现象的发生在两个遥远的相关apicomplexan寄生虫，弓形虫，弓形虫病的代理人，和啮齿动物疟疾寄生虫伯氏疟原虫。小RNA组分的小规模分子表征T。gondii发现了10种不同的tRNA的核酸内切加工，在反密码子环和3 '端CCA序列上游切割，产生5'端或3 '端半tRNA。T.刚地疟原虫和伯氏疟原虫在从宿主细胞中排出时以及响应阶段分化、氨基酸饥饿和热休克时表现出可变的tRNA切割速率。此外，T.弓形虫和减毒伯氏疟原虫的tRNA裂解率高于强毒株。有趣的是，半tRNA的产量显着较高的代谢静止缓子和孢子阶段的T。与快速生长的速殖子相比总的来说，我们的研究结果首次揭示了顶复门寄生虫中tRNA裂解的发生，并表明在这一重要的生物群中半tRNA的产生和生长速率之间的关系。(C)2013爱思唯尔有限公司版权所有。
Several lines of evidence demonstrated that organisms ranging from bacteria to higher animals possess a regulated endonucleolytic cleavage pathway producing half-tRNA fragments. In the present study, we investigated the occurrence of this phenomenon in two distantly related apicomplexan parasites, Toxoplasma gondii, the agent of toxoplasmosis, and the rodent malaria parasite Plasmodium berghei. A low-scale molecular characterization of the small RNA fraction of T. gondii revealed the endonucleolytic processing of 10 distinct tRNA species, with cleavage in the anticodon loop and upstream of the 3'-terminal CCA sequence yielding 5'- or 3'-end half-tRNAs. T. gondii and P. berghei exhibited variable rates of tRNA cleavage upon egress from host cells and in response to stage differentiation, amino acid starvation and heat-shock. Moreover, avirulent isolates of T. gondii and attenuated P. berghei parasites showed a higher rate of tRNA cleavage than virulent strains. Interestingly, half-tRNA production was significantly higher in the metabolically quiescent bradyzoite and sporozoite stages of T. gondii, compared to the fast-growing tachyzoite. Collectively, our findings shed light for the first time on the occurrence of tRNA cleavage in apicomplexan parasites and suggest a relationship between half-tRNA production and growth rate in this important group of organisms. (C) 2013 Elsevier B.V. All rights reserved.