Lymphocytes are generated from multipotential hematopoietic stem cells in an ordered process of terminal differentiation. Several transcription factors regulate distinct steps of lymphocyte differentiation, including the specification and commitment of progenitor cells to a particular cell lineage and the maturation of these cells.

However, it is still unclear which extracellular signals, provided by stromal niches, regulate the expression and activity of these transcriptional determinants of lymphopoiesis, and how specific signals and transcription factors work together to coordinate the complex differentiation process. As many regulators of lymphopoiesis are also expressed in other cell types, it is important to understand the combinatorial code of these proteins and to elucidate the mechanisms by which multiple extracellular signals are integrated at transcriptional control sequences.

Other questions include the allele-specific expression and rearrangement of antigen receptor genes, which are regulated by differential chromatin structures, changes in gene localization and feedback mechanisms of antigen receptor signaling.