Genome wide mapping of ETV6 binding sites in pre-B leukemic cells

Background: Genetic alterations in the transcriptional repressor ETV6 are associated with hematological malignancies. Notably, the t(12;21) translocation leading to an ETV6-AML1 fusion gene is the most common genetic alteration found in childhood acute lymphoblastic leukemia. Moreover, most of these patients also lack ETV6 expression, suggesting a tumor suppressor function. Results: To gain insights on ETV6 DNA-binding specificity and genome wide transcriptional regulation capacities, we performed chromatin immunoprecipitation experiments coupled to deep sequencing in a t(12;21)-positive pre-B leukemic cell line. This strategy led to high quality ETV6-bound regions. ETV6 binding is mostly cell type-specific as only few regions are shared with other blood cell subtypes. Peaks localization and motif enrichment analyses revealed a unique binding profile that is associated with the presence of the ETV6-AML1 fusion product. Conclusions: We described the first ETV6 binding map in the t(12;21) background. This study highlighted the complex and unique interplay between ETV6 and ETV6-AML1 and underscored the highly regulated mechanisms of ETV6 binding. ETV6 inactivation observed in this context could induce specific transcriptional changes promoting leukemic transformation. Overall design: Genome wide ETV6 binding sites were identified through chromatin immunoprecipitation sequencing in ETV6-HA transduced Reh cells compared to ETV6 (negative IP control), each in triplicates