Myeloid biologyZinc-finger transcription factor Gfi-1: versatile regulator of lymphocytes, neutrophils and hematopoietic stem cellsHock, Hannoa,b; Orkin, Stuart Ha,cAuthor Information aDivision of Hematology/Oncology, Children's Hospital, Dana Farber Cancer Institute, Boston, Massachusetts, USA bMassachusetts General Hospital Cancer Center and Center of Regenerative Medicine, Boston, Massachusetts, USA cHoward Hughes Medical Institute, Boston, Massachusetts, USA Correspondence to Hanno Hock, MGH Cancer Center and Center of Regenerative Medicine, Simches Building, CPZN 4200 4th floor, 185 Cambridge Street, Boston, MA 02114, USA Tel: +1 617 643 3145; fax: +1 617 643 3170; e-mail: [email protected]; [email protected] Current Opinion in Hematology: January 2006 - Volume 13 - Issue 1 - p 1-6 doi: 10.1097/01.moh.0000190111.85284.8f Buy Metrics Abstract 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/EBPα, and C/EBPε. 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. © 2006 Lippincott Williams & Wilkins, Inc.