Short interfering RNA induced generation and translation of stable 5' mRNA cleavage intermediates.
Biochim Biophys Acta
; 1859(8): 1034-42, 2016 08.
Article
em En
| MEDLINE
| ID: mdl-27321990
ABSTRACT
Sequence-specific degradation of homologous mRNA is the main mechanism by which short-interfering RNAs (siRNAs) suppress gene expression. Generally, it is assumed that the mRNA fragments resulting from Ago2 cleavage are rapidly degraded, thus making the transcript translation-incompetent. However, the molecular mechanisms involved in the post-cleavage mRNA decay are not completely understood and the fate of cleavage intermediates has been poorly studied. Using specific siRNAs and short-hairpin RNAs (shRNAs) we show that the 5' and 3' mRNA cleavage fragments of human papilloma virus type 16 (HPV-16) E6/7 mRNA, over-expressed in cervical malignancies, are unevenly degraded. Intriguingly, the 5' mRNA fragment was more abundant and displayed a greater stability than the corresponding 3' mRNA fragment in RNAi-treated cells. Further analysis revealed that the 5' mRNA fragment was polysome-associated, indicating its active translation, and this was further confirmed by using tagged E7 protein to show that C-terminally truncated proteins were produced in treated cells. Overall, our findings provide new insight into the degradation of siRNA-targeted transcripts and show that RNAi can alter protein expression in cells as a result of preferential stabilization and translation of the 5' cleavage fragment. These results challenge the current model of siRNA-mediated RNAi and provide a significant step forward towards understanding non-canonical pathways of siRNA gene silencing.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Biossíntese de Proteínas
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RNA Mensageiro
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Inativação Gênica
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Células Epiteliais
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Proteínas E7 de Papillomavirus
Tipo de estudo:
Prognostic_studies
Limite:
Animals
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Female
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Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Austrália