Our earlier studies of the transcriptional regulation of cytokine gene expression, led us to isolate and characterize the transcription factor MEF (myeloid elf-1 like factor), which belongs to the well-known ETS family of TFs. MEF was cloned from a megakaryocytic leukemia cDNA library and shown to be a potent transcriptional activator of gene expression by our laboratory. Many aspects of its role in hematopoiesis remain undiscovered, but the availability of MEF-deficient mice, recently generated in the laboratory, has allowed us to identify a role for MEF in the behavior of hematopoietic stem cells (HSCs). Little is known about the transcriptional pathways that regulate self-renewal and quiescence of HSCs. Thus the availability of these mice will provide a model system to study these vital processes.
Characterizing the self-renewal potential of HSCs provides several potential clinical applications, both for stem cell transplantation and for ex vivo gene transfer. Lack of MEF also has profound effects on the development of the NK and NK T cell lymphoid lineages, which play important roles in preventing the growth of tumors. These cell types constitute the innate immune response, thus future studies will define the role of MEF in innate immunity and stem cell renewal.
