Non-coding genetic variation in GATA3 increases acute lymphoblastic leukemia risk through local and global changes in chromatin conformation

Inherited non-coding genetic variants confer significant disease susceptibility in many cancers. However, the molecular processes by which germline variants contribute to somatic lesions are poorly understood. We performed targeted sequencing in 5,008 patients and identified a key regulatory germline variant in GATA3 strongly associated with Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL). By creating an isogenic cellular model with a CRISPR-Cas9 system, we showed that this variant activated a strong enhancer that significantly upregulated GATA3 transcription, which in turn reshaped the global chromatin accessibility and 3D genome organization. Remarkably, this genotype switch induced a chromatin loop between the CRLF2 oncogene and a distal enhancer, similar to the somatically acquired super-enhancer hijacking event in patients. GATA3 genotype-related alterations in transcriptional control and 3D chromatin organization were further validated in Ph-like ALL patients. Finally, we showed that GATA3 directly regulates CRLF2 and potentiates the oncogenic effects of JAK-STAT signaling in leukemogenesis. Altogether, our results provide evidence for a novel mechanism by which a germline non-coding variant contributes to oncogene activation epigenetic regulation and 3D genome reprogramming. GM12878 cells were engineered to knock in the A allele at rs3824462. Consequences of the epigenetics and chromatin topology change between GM12878 cells/patients(CC) and engineered cells/patients(AA) were investigated using ChIP-seq, RNA-seq, and Hi-C.