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Activation of the LMO2 oncogene through a somatically acquired neomorphic promoter in T-Cell Acute Lymphoblastic Leukemia

ABSTRACT: Somatic mutations within non-coding genomic regions that aberrantly activate oncogenes have remained poorly characterized. Here we describe recurrent activating intronic mutations of LMO2, a prominent oncogene in T-cell acute lymphoblastic leukaemia (T-ALL). Heterozygous mutations were identified in PF-382 and DU.528 T-ALL cell lines, in addition to 3.7% (6/160) of paediatric and 5.5% (9/163) of adult T-ALL patient samples. The majority of indels harbor de novo MYB, ETS1 or RUNX1 consensus binding sites. Analysis of 5’-capped RNA transcripts in mutant cell lines identified the usage of an intermediate promoter site, with consequential monoallelic LMO2 overexpression. CRISPR/Cas9-mediated disruption of the mutant allele in PF-382 cells markedly downregulated LMO2 expression, establishing clear causality between the mutation and oncogene dysregulation. Furthermore, the spectrum of CRISPR/Cas9-derived mutations provide important insights into the interconnected contributions of functional transcription factor binding. Finally, these mutations occur in the same intron as retroviral integration sites in gene therapy induced T-ALL, suggesting that such events occur at preferential sites in the non-coding genome.

ORGANISM(S): Homo sapiens

PROVIDER: GSE94000 | GEO | 2017/03/15

SECONDARY ACCESSION(S): PRJNA363039

REPOSITORIES: GEO

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