Ebf Restricts Alternate Lineage Options And Promotes B Cell Fate Commitment Independently Of Pax5

Alternate lineage restriction and B cell fate commitment require the transcription factor Pax5, but the functions of EBF, in these processes remain largely unexplored. In the absence of EBF, expandable and clonal lymphoid progenitors retain considerable myeloid potential. Conversely, ectopic expression of EBF in multipotential progenitors directs B cell generation at the expense of myeloid cell fates. EBF induces Pax5 and antagonizes expression of C/EBPα, PU.1 and Id2. Importantly, sustained expression of EBF in Pax5−/− hematopoietic progenitors is sufficient to block their myeloid and T lineage potentials in vivo. Furthermore, in Pax5−/− pro‐B cells increased EBF expression represses alternate lineage genes. Thus, EBF can restrict alternate lineage choice and promote B cell fate commitment independently of Pax5.