Homeobox Protein B4 (HOXB4)

HOXB4 is a member of the Antp homeobox family and encodes a nuclear protein with a homeobox DNA-binding domain. It is included in a cluster of homeobox B genes located on chromosome 17. The encoded protein functions as a sequence-specific transcription factor that is involved in development. Intracellular or ectopic expression of this protein expands hematopoietic stem and progenitor cells in vivo and in vitro, making it a potential candidate for therapeutic stem cell expansion. Expression of Hoxb4 in primitive progenitors combined with culture on hematopoietic stroma induced a switch to the definitive HSC phenotype. These progenitors engrafted lethally irradiated adults and contributed to long-term, multilineage hematopoiesis in primary and secondary recipients.