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. 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