Key pioneer transcription factor of B-cell specification and commitment (PubMed:27807034). Recognizes variations of the palindromic sequence 5'-ATTCCCNNGGGAATT-3'. Operates in a transcription factor network to activate B-cell-specific genes and repress genes associated with alternative cell fates. For instance, positively regulates many B-cell specific genes including BCR or CD40 while repressing genes that direct cells into alternative lineages, including GATA3 and TCF7 for the T-cell lineage. In addition to its role during lymphopoiesis, controls the thermogenic gene program in adipocytes during development and in response to environmental cold (By similarity). (Microbial infection) Acts as a chromatin anchor for Epstein-Barr virus EBNA2 to mediate the assembly of EBNA2 chromatin complexes in B-cells (PubMed:28968461). In addition, binds to the viral LMP1 proximal promoter and promotes its expression during latency (PubMed:26819314). Homodimer (PubMed:20592035). Interacts with ZNF423 and ZNF521, leading to prevent EBF1 to bind DNA and activate target genes (PubMed:14630787). Interacts with CCR4-NOT component CNOT3 (PubMed:14630787). (Microbial infection) Interacts with Epstein-barr virus protein EBNA2. Belongs to the COE family.