A population of tRNA-derived small RNAs is actively produced in Trypanosoma cruzi and recruited to specific cytoplasmic granules
A population of tRNA-derived small RNAs is actively produced in Trypanosoma cruzi and recruited to specific cytoplasmic granules
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DOI：
10.1016/j.molbiopara.2010.02.003
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发表时间：
2010-06-01
影响因子：
1.5
通讯作者：
Cayota, Alfonso
中科院分区：
文献类型：
--
作者：
Garcia-Silva, Maria Rosa;Frugier, Magali;Cayota, Alfonso
在过去的几年里，一个不断扩大的小RNA家族（即microRNA，siRNA和piRNA）被认为是不同形式的基因沉默和染色质组织的关键参与者。这些小RNA的效应子功能通过在其中心含有Argonaute/Piwi蛋白的核糖核蛋白（RNP）复合物实现。虽然这些蛋白质和它们的小RNA相关机制可以追溯到真核生物的共同祖先，但这种机制似乎在一些单细胞生物（包括克氏锥虫）中完全丢失或广泛简化，这些生物无法触发RNAi相关现象。推测在这些生物体中存在交替的小RNA介导的途径，我们构建并分析了来自T.克鲁兹我们的研究结果表明，一个丰富的类tRNA衍生的小RNA的生产优先限制特定的isoacceptor和生产更强调营养胁迫下。这些小的tRNA优先来源于成熟tRNA的5'端，并被募集到独特的细胞质颗粒中。我们的数据支持这样的观点，即tRNA切割不太可能是非特异性降解的结果，而是一个受控的过程，其生物学意义仍有待阐明。(C)2010爱思唯尔有限公司版权所有。
Over the last years an expanding family of small RNAs (i.e. microRNAs, siRNAs and piRNAs) was recognized as key players in diverse forms of gene silencing and chromatin organization. Effectors functions of these small RNAs are achieved through ribonucleoprotein (RNP) complexes containing at their center an Argonaute/Piwi protein. Although these proteins and their small RNA-associated machinery can be traced back to the common ancestor of eukaryotes, this machinery seems to be entirely lost or extensively simplified in some unicellular organisms including Trypanosoma cruzi, which are unable to trigger RNAi related phenomena. Speculating about the presence of alternate small RNA-mediated pathways in these organisms, we constructed and analyzed a size-fractionated cDNA library (20-35 nt) from epimastigotes forms of T. cruzi. Our results showed the production of an abundant class of tRNA-derived small RNAs preferentially restricted to specific isoacceptors and whose production was more accentuated under nutritional stress. These small tRNAs derived preferentially from the 5' halves of mature tRNAs and were recruited to distinctive cytoplasmic granules. Our data favor the idea that tRNA cleavage is unlikely to be the consequence of non-specific degradation but a controlled process, whose biological significance remains to be elucidated. (C) 2010 Elsevier B.V. All rights reserved.