Zinc-finger transcription factor Gfi-1: versatile regulator of lymphocytes, neutrophils and hematopoietic stem cells

Purpose of review. Gfi-1, originally identified as a transcriptional repressor in lymphoid cells, is now recognized to have essential, independent functions in neutrophil maturation and hematopoietic stem cell biology. Here we review recent studies pertaining to Gfi-1 and its cell context specific functions in hematopoietic development. Recent findings. Progress in mapping the precise timing of requirements for myeloid transcription factors during hematopoietic development reveals a more refined picture of their sequence of action, We contrast Gfi-1's role in neutrophil development with PU.1, C/EBP alpha, and C/EBP epsilon. Gfi-1 has been found to be a major regulator of adult hematopoietic stem cells. It is required for restricting the proliferation of hematopoietic stem cells and maintaining their functional integrity. We discuss its role and compare its function with that of other regulators recently implicated in the biology of hematopoietic stem cells. Summary. Considerable progress has been made in understanding Gfi-1's context-sensitive roles at defined stages of hematopoietic differentiation.