The HDAC7-TET2 epigenetic axis is essential during early B lymphocyte development

B lymphopoiesis is the result of several cell lineage choices and differentiation steps whose perturbation leads to B cell malignancies. Cellular transitions for B cell generation have been associated with gene activation and silencing by networks of B cell specific transcription factors (TFs) and dynamic changes in DNA methylation. How gene repression is established and which lineage-specific transcriptional repressors are involved during B cell lymphopoiesis are still not totally understood. Here, by using our in vivo experimental approach, we have found that HDAC7 represses Tet2 enzyme in pro-B cells. In fact, HDAC7 deficient pro-B cells show a significant increase in the percentage of global 5-hydroxymethylation. To prove the role of HDAC7 in 5-hydroxymethylation, we have performed a genome-wide experimental approach. hMeDIP-sequencing experiments reveal an increase in the enrichment of this epigenetic modification at many loci related to lineage inappropriate genes. Our results corroborate that HDAC7 is an essential transcriptional regulator during early B cell development that silences lineage or functionally inappropriate genes and unveil an unexpected role of a class IIa HDAC in controlling DNA methylation Overall design: Study of hydroxymethylation genomic distribution in murine progenitor B cells depending on the presence of the protein HDAC7