LRPPRC/SLIRP suppresses PNPase-mediated mRNA decay and promotes polyadenylation in human mitochondria.
Nucleic Acids Res
; 40(16): 8033-47, 2012 Sep.
Article
em En
| MEDLINE
| ID: mdl-22661577
ABSTRACT
In human mitochondria, 10 mRNAs species are generated from a long polycistronic precursor that is transcribed from the heavy chain of mitochondrial DNA, in theory yielding equal copy numbers of mRNA molecules. However, the steady-state levels of these mRNAs differ substantially. Through absolute quantification of mRNAs in HeLa cells, we show that the copy numbers of all mitochondrial mRNA species range from 6000 to 51,000 molecules per cell, indicating that mitochondria actively regulate mRNA metabolism. In addition, the copy numbers of mitochondrial mRNAs correlated with their cellular half-life. Previously, mRNAs with longer half-lives were shown to be stabilized by the LRPPRC/SLIRP complex, which we find that cotranscriptionally binds to coding sequences of mRNAs. We observed that the LRPPRC/SLIRP complex suppressed 3' exonucleolytic mRNA degradation mediated by PNPase and SUV3. Moreover, LRPPRC promoted the polyadenylation of mRNAs mediated by mitochondrial poly(A) polymerase (MTPAP) in vitro. These findings provide a framework for understanding the molecular mechanism of mRNA metabolism in human mitochondria.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Polirribonucleotídeo Nucleotidiltransferase
/
RNA
/
RNA Mensageiro
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Proteínas de Ligação a RNA
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Estabilidade de RNA
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Poliadenilação
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Proteínas de Neoplasias
Limite:
Humans
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article