Titre
A somatic mutation in the 5'UTR of BRCA1 gene in sporadic breast cancer causes down-modulation of translation efficiency.
Type
article
Institution
Externe
Périodique
Auteur(s)
Signori, E.
Auteure/Auteur
Bagni, C.
Auteure/Auteur
Papa, S.
Auteure/Auteur
Primerano, B.
Auteure/Auteur
Rinaldi, M.
Auteure/Auteur
Amaldi, F.
Auteure/Auteur
Fazio, V.M.
Auteure/Auteur
Liens vers les personnes
ISSN
0950-9232
Statut éditorial
Publié
Date de publication
2001-07-27
Volume
20
Numéro
33
Première page
4596
Dernière page/numéro d’article
4600
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Publication Status: ppublish
Résumé
Mutations in the 5' UTR which cause increment/decrement of translation efficiency have been recently described as a novel molecular mechanism of disease. Alterations in the consensus sequence for the translation initiation may promote context-dependent leaky scanning of ribosomes and/or initiation from a downstream AUG codon. Initiation of translation from a downstream in-frame AUG codon in BRCA1 gene was recently identified in normal cells and possibly in breast cancer. Here we present further insight into BRCA1 translational pathophysiology investigating the role of the canonical structure of the initiation consensus sequence of BRCA1. We have analysed the effect of a somatic point mutation (117 G>C) in position -3 with respect to the AUG of the BRCA1 gene, identified in a highly aggressive sporadic breast cancer. We constructed chimeric genes encoding the luciferase reporter sequence downstream of the wild type or the mutated BRCA1 5'UTR. These transcripts were tested for their activity in in vitro and in vivo systems. In in vitro transcription/translation assays the estimated translation efficiency of the construct with the mutated BRCA1 5'UTR was 30-50% lower than that with the wild type BRCA1 5'UTR. The same chimeric genes were analysed for their expression in vivo by transient transfection in human cells. While the two constructs were equally transcribed, the plasmid carrying the mutated sequence produced 70% less luciferase activity compared to the wild type sequence. Finally, to obtain a direct evaluation on translational efficiency in vivo, we analysed mRNA translation on translationally active and non-active ribosomes separated from transfected cells. Mutant mRNA was partially localized in subpolysomal particles analytically confirming a polysome recruitment defect. Thus, characterization of BRCA1 5'UTR and translation efficiency seems to provide new insight into BRCA1 role in breast and ovarian cancer pathogenesis.
Sujets
PID Serval
serval:BIB_93F33A8E7C3C
PMID
Open Access
Oui
Date de création
2017-03-06T16:23:45.714Z
Date de création dans IRIS
2025-05-20T23:38:32Z