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Comprehensive splicing functional analysis of DNA variants of the BRCA2 gene by hybrid minigenes.
Acedo, Alberto; Sanz, David J; Durán, Mercedes; Infante, Mar; Pérez-Cabornero, Lucía; Miner, Cristina; Velasco, Eladio A.
Afiliación
  • Acedo A; Grupo de Splicing y Cáncer, Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Valladolid, Sanz y Forés 3, Valladolid 47003, Spain.
Breast Cancer Res ; 14(3): R87, 2012 May 25.
Article en En | MEDLINE | ID: mdl-22632462
INTRODUCTION: The underlying pathogenic mechanism of a large fraction of DNA variants of disease-causing genes is the disruption of the splicing process. We aimed to investigate the effect on splicing of the BRCA2 variants c.8488-1G > A (exon 20) and c.9026_9030del (exon 23), as well as 41 BRCA2 variants reported in the Breast Cancer Information Core (BIC) mutation database. METHODS: DNA variants were analyzed with the splicing prediction programs NNSPLICE and Human Splicing Finder. Functional analyses of candidate variants were performed by lymphocyte RT-PCR and/or hybrid minigene assays. Forty-one BIC variants of exons 19, 20, 23 and 24 were bioinformatically selected and generated by PCR-mutagenesis of the wild type minigenes. RESULTS: Lymphocyte RT-PCR of c.8488-1G > A showed intron 19 retention and a 12-nucleotide deletion in exon 20, whereas c.9026_9030del did not show any splicing anomaly. Minigene analysis of c.8488-1G > A displayed the aforementioned aberrant isoforms but also exon 20 skipping. We further evaluated the splicing outcomes of 41 variants of four BRCA2 exons by minigene analysis. Eighteen variants presented splicing aberrations. Most variants (78.9%) disrupted the natural splice sites, whereas four altered putative enhancers/silencers and had a weak effect. Fluorescent RT-PCR of minigenes accurately detected 14 RNA isoforms generated by cryptic site usage, exon skipping and intron retention events. Fourteen variants showed total splicing disruptions and were predicted to truncate or eliminate essential domains of BRCA2. CONCLUSIONS: A relevant proportion of BRCA2 variants are correlated with splicing disruptions, indicating that RNA analysis is a valuable tool to assess the pathogenicity of a particular DNA change. The minigene system is a straightforward and robust approach to detect variants with an impact on splicing and contributes to a better knowledge of this gene expression step.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Neoplasias de la Mama / Empalme del ARN / Proteína BRCA2 / Genes BRCA2 Tipo de estudio: Prognostic_studies Límite: Female / Humans Idioma: En Revista: Breast Cancer Res Asunto de la revista: NEOPLASIAS Año: 2012 Tipo del documento: Article País de afiliación: España Pais de publicación: Reino Unido

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Neoplasias de la Mama / Empalme del ARN / Proteína BRCA2 / Genes BRCA2 Tipo de estudio: Prognostic_studies Límite: Female / Humans Idioma: En Revista: Breast Cancer Res Asunto de la revista: NEOPLASIAS Año: 2012 Tipo del documento: Article País de afiliación: España Pais de publicación: Reino Unido