An oncogenic super-enhancer formed through somatic mutation of a noncoding intergenic element
2014
Mansour, Marc R. | Abraham, Brian J. | Anders, Lars | Berezovskaya, Alla | Gutiérrez, Alejandro | Durbin, Adam D. | Etchin, Julia | Lawton, Lee | Sallan, Stephen E. | Silverman, Lewis B. | Loh, Mignon L. | Hunger, Stephen P. | Sanda, Takaomi | Young, Richard A. | Look, A Thomas
In certain human cancers, the expression of critical oncogenes is driven from large regulatory elements, called super-enhancers, that recruit much of the cell’s transcriptional apparatus and are defined by extensive acetylation of histone H3 lysine 27 (H3K27ac). In a subset of T-cell acute lymphoblastic leukemia (T-ALL) cases, we found that heterozygous somatic mutations are acquired that introduce binding motifs for the MYB transcription factor in a precise noncoding site, which creates a super-enhancer upstream of the TAL1 oncogene. MYB binds to this new site and recruits its H3K27 acetylase–binding partner CBP, as well as core components of a major leukemogenic transcriptional complex that contains RUNX1, GATA-3, and TAL1 itself. Additionally, most endogenous super-enhancers found in T-ALL cells are occupied by MYB and CBP, which suggests a general role for MYB in super-enhancer initiation. Thus, this study identifies a genetic mechanism responsible for the generation of oncogenic super-enhancers in malignant cells.
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