Key pioneer transcription factor of B-cell specification and commitment (PubMed:1915300, PubMed:7542362, PubMed:23812095). Recognizes variations of the palindromic sequence 5'-ATTCCCNNGGGAATT-3' (PubMed:20876732). Operates in a transcription factor network to activate B-cell-specific genes and repress genes associated with alternative cell fates (PubMed:23812095, PubMed:20451411). 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 (PubMed:23812095, PubMed:20451411). In addition to its role during lymphopoiesis, controls the thermogenic gene program in adipocytes during development and in response to environmental cold (PubMed:32130892). Homodimer (PubMed:9151732, PubMed:20876732). Interacts with ZNF423 and ZNF521, leading to prevent EBF1 to bind DNA and activate target genes (By similarity). Interacts with CCR4-NOT component CNOT3 (By similarity). Expressed at high levels in early B-cells, spleen, lymph node and adipose tissue, and at low levels in heart, brain, skeletal muscle and kidney. In adult expressed in olfactory epithelium, in spleen, and at a lesser extent in Purkinje cells of the cerebellum, heart, kidney, lung, thymus and testis. In embryo expressed in dorsal thalamus and epithalamus, at a lower level in mesencephalon and in the caudal rhombencephalon, in the postmitotic cells of developing retina, highly in developing spinal cord, dorsal root ganglia, trigeminal ganglia and in glossopharyngeal nerve ganglia, in developing inner ear. First detected at 9.5 dpc. Targeted disruption in mice results in animals with a severe defect in early B-cell development. EBF1 heterozygous mice exhibit an approximately 2-fold decrease in the number of cells in the pro-B lymphocyte compartment, indicating that normal B-cell development depends on the presence of two wild-type EBF1 alleles (PubMed:7542362). Adipocyte-specific deletion mutant reveals a modest reduction of UCP1 expression, a mitochondrial protein responsible for thermogenic respiration. Double mutants EBF1/EBF2 show a more severe reduction of UCP1 expression (PubMed:32130892). Belongs to the COE family.