A conserved stem-loop structure in the 3' untranslated region of procyclin mRNAs regulates expression in Trypanosoma brucei.
A conserved stem-loop structure in the 3' untranslated region of procyclin mRNAs regulates expression in Trypanosoma brucei.
复制标题
前环素 mRNA 3 非翻译区中的保守茎环结构可调节布氏锥虫的表达。
DOI：
--
复制
发表时间：
1994
影响因子：
11.1
通讯作者：
Isabel Roditi
中科院分区：
文献类型：
--
作者：
Adrian Hehl;Erik Vassella;Richard Braun;Isabel Roditi
在哺乳动物宿主和采采蝇媒介之间循环的非洲锥虫必须做好在不同环境中生存的准备。阶段特异性基因表达的控制无疑是成功适应的关键之一，但迄今为止尚未定义任何调控元件。前环蛋白（也称为前环酸性重复蛋白）在果蝇中的前环和上鞭毛体形式的表面上特异性表达。前环素基因已经以血流形式转录，但当寄生虫开始分化为前环素形式时，首先检测到稳定的 mRNA，然后是蛋白质。我们现在已经鉴定出一个 16 个碱基的区域，该区域构成了不同前环素 mRNA 的 3' 非翻译区域中预测的茎环结构的一部分；该 16 聚体的序列和二级结构似乎都是原环形式报告基因有效翻译所必需的。稳态 mRNA 的水平、其聚腺苷酸化及其在细胞中的分布均不受该元件存在或不存在的影响。单独删除 16 聚体比删除或逆转整个 3' 非翻译区和侧翼区更能降低表达，表明在同一 3' 非翻译区中存在额外的负调控元件。
African trypanosomes that cycle between mammalian hosts and the tsetse fly vector must be poised to survive in different environments. The control of stage-specific gene expression is undoubtedly one of the keys to successful adaptation, but no regulatory elements have been defined to date. Procyclins (also known as procyclic acidic repetitive proteins) are specifically expressed on the surface of procyclic and epimastigote forms in the fly. Procyclin genes are already transcribed in bloodstream forms, but stable mRNA, and later the protein, are first detected when the parasites begin to differentiate into procyclic forms. We have now identified a region of 16 bases that forms part of a predicted stem-loop structure in the 3' untranslated regions of different procyclin mRNAs; both the sequence and the secondary structure of this 16-mer appear to be required for efficient translation of a reporter gene in procyclic forms. The level of steady-state mRNA, its polyadenylylation, and its distribution in the cell are all unaffected by the presence or absence of this element. Deletion of the 16-mer alone reduces expression more than removal or reversal of the entire 3' untranslated region and flanking region, suggesting that there are additional negative regulatory elements in the same 3' untranslated region.