E2A is a member of the E protein (class I) family of helix-loop-helix transcription factors. E proteins play a critical role in lymphopoiesis, and the protein is required for B and T lymphocyte development. Alternative splicing generates two E2A isoforms (E47 and E12) that are actively involved in B cell lineage commitment, B cell maturation, IgK V-J rearrangement, peripheral B cell development, and tumor suppression. E12 and E47 are nuclear proteins that form heterodimers with Myo D transcription factors and play a role in determining tissue-specific cell fate during embryogenesis. E12 and E47 bind to the kappa-E2 site in the kappa immunoglobulin gene enhancer.
