Site- and allele-specific polycomb dysregulation in T-cell leukaemia.
Nat Commun
; 6: 6094, 2015 Jan 23.
Article
en En
| MEDLINE
| ID: mdl-25615415
ABSTRACT
T-cell acute lymphoblastic leukaemias (T-ALL) are aggressive malignant proliferations characterized by high relapse rates and great genetic heterogeneity. TAL1 is amongst the most frequently deregulated oncogenes. Yet, over half of the TAL1(+) cases lack TAL1 lesions, suggesting unrecognized (epi)genetic deregulation mechanisms. Here we show that TAL1 is normally silenced in the T-cell lineage, and that the polycomb H3K27me3-repressive mark is focally diminished in TAL1(+) T-ALLs. Sequencing reveals that >20% of monoallelic TAL1(+) patients without previously known alterations display microinsertions or RAG1/2-mediated episomal reintegration in a single site 5' to TAL1. Using 'allelic-ChIP' and CrispR assays, we demonstrate that such insertions induce a selective switch from H3K27me3 to H3K27ac at the inserted but not the germline allele. We also show that, despite a considerable mechanistic diversity, the mode of oncogenic TAL1 activation, rather than expression levels, impact on clinical outcome. Altogether, these studies establish site-specific epigenetic desilencing as a mechanism of oncogenic activation.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Regulación Leucémica de la Expresión Génica
/
Alelos
/
Leucemia-Linfoma Linfoblástico de Células T Precursoras
/
Proteínas del Grupo Polycomb
Límite:
Adult
/
Humans
Idioma:
En
Revista:
Nat Commun
Asunto de la revista:
BIOLOGIA
/
CIENCIA
Año:
2015
Tipo del documento:
Article
País de afiliación:
Francia