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EMBO J. 2008 Jun 4;27(11):1596-608. doi: 10.1038/emboj.2008.87. Epub 2008 May 8.

3' adenylation determines mRNA abundance and monitors completion of RNA editing in T. brucei mitochondria.

Author information

1
Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, CA 92697, USA.

Abstract

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.

PMID:
18464794
PMCID:
PMC2426725
DOI:
10.1038/emboj.2008.87
[Indexed for MEDLINE]
Free PMC Article

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