3′ adenylation determines mRNA abundance and monitors completion of RNA editing in T-brucei mitochondria
3′ adenylation determines mRNA abundance and monitors completion of RNA editing in T-brucei mitochondria
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DOI：
10.1038/emboj.2008.87
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发表时间：
2008-06-04
期刊：
影响因子：
11.4
通讯作者：
Aphasizhev, Ruslan
中科院分区：
文献类型：
--
作者：
Etheridge, Ronald D.;Aphasizheva, Inna;Aphasizhev, Ruslan
原生动物寄生虫布氏锥虫线粒体基因组的表达是转录后控制的，需要广泛的U-插入/缺失mRNA编辑。据报道，在线粒体提取物中，3'腺苷酸化影响合成的编辑和预编辑mRNA的降解动力学。我们已经确定并表征了一种线粒体聚腺苷酸聚合酶，称为KPAP 1，并确定了聚腺苷酸复合物中的主要多肽。KPAP 1表达的抑制消除了通常在线粒体mRNA中发现的短和长A尾，并减少了从未编辑和编辑的转录物的丰度。预编辑的mRNA不会因缺乏3'腺苷酸化而不稳定，而短A尾是必需的并且足以维持部分编辑的、完全编辑的和从未编辑的mRNA的稳态水平。由单个指导RNA指导的编辑足以在编辑的分子中施加对短A尾的要求。在完成编辑过程后，短A-尾作为（A/U）杂聚物延伸到先前被认为是长聚（A）尾的结构中。这些数据提供了锥虫中线粒体mRNA的3'加工和编辑之间的功能相互作用的第一个直接证据。
Expression of the mitochondrial genome in protozoan parasite Trypanosoma brucei is controlled post-transcriptionally and requires extensive U-insertion/deletion mRNA editing. In mitochondrial extracts, 3' adenylation reportedly influences degradation kinetics of synthetic edited and pre-edited mRNAs. We have identified and characterized a mitochondrial poly(A) polymerase, termed KPAP1, and determined major polypeptides in the polyadenylation complex. Inhibition of KPAP1 expression abrogates short and long A-tails typically found in mitochondrial mRNAs, and decreases the abundance of never-edited and edited transcripts. Pre-edited mRNAs are not destabilized by the lack of 3' adenylation, whereas short A-tails are required and sufficient to maintain the steady-state levels of partially edited, fully edited, and never-edited mRNAs. The editing directed by a single guide RNA is sufficient to impose a requirement for the short A-tail in edited molecules. Upon completion of the editing process, the short A-tails are extended as (A/U) heteropolymers into structures previously thought to be long poly(A) tails. These data provide the first direct evidence of functional interactions between 3' processing and editing of mitochondrial mRNAs in trypanosomes.