Focal deletions of a promoter tether activate the IRX3 oncogene in T-cell acute lymphoblastic leukemia
Details
Publication Year 2024-11-28,Volume 144,Issue #22,Page 2319-2326
Journal Title
Blood
Publication Type
Research article
Abstract
Oncogenes can be activated in cis through multiple mechanisms including enhancer hijacking events and noncoding mutations that create enhancers or promoters de novo. These paradigms have helped parse somatic variation of noncoding cancer genomes, thereby providing a rationale to identify noncanonical mechanisms of gene activation. Here we describe a novel mechanism of oncogene activation whereby focal copy number loss of an intronic element within the FTO gene leads to aberrant expression of IRX3, an oncogene in T-cell acute lymphoblastic leukemia (T-ALL). Loss of this CTCF-bound element downstream to IRX3 (+224 kb) leads to enhancer hijack of an upstream developmentally active super-enhancer of the CRNDE long noncoding RNA (-644 kb). Unexpectedly, the CRNDE super-enhancer interacts with the IRX3 promoter with no transcriptional output until it is untethered from the FTO intronic site. We propose that "promoter tethering" of oncogenes to inert regions of the genome is a previously unappreciated biological mechanism preventing tumorigenesis.
Publisher
American Society of Hematology
Keywords
Humans; *Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/genetics/pathology; *Promoter Regions, Genetic; *Homeodomain Proteins/genetics/metabolism; *Transcription Factors/genetics/metabolism; Alpha-Ketoglutarate-Dependent Dioxygenase FTO/genetics/metabolism; Oncogenes; Enhancer Elements, Genetic; Gene Expression Regulation, Leukemic; Sequence Deletion; RNA, Long Noncoding/genetics; Introns; CCCTC-Binding Factor/genetics/metabolism
Department(s)
Laboratory Research
Open Access at Publisher's Site
https://doi.org/10.1182/blood.2024024300
Terms of Use/Rights Notice
Refer to copyright notice on published article.


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