A unifying model for the effects of different Gata1 mutations in hematopoiesis. All of the different Gata1 mutations described up to now affect the end stage of erythroid, megakaryocytic, and mast cell differentiation.^1,56  Several Gata1 mutations also affect the biology of stem/progenitor cells. The Gata1s mutation increases the proliferation potential of fetal progenitor cells.⁵⁷  We propose that the Gata1^0.5 mutation, being associated with myeloid and B-lymphoid leukemia,⁵⁸  may act at the restriction point between hematopoietic stem cells (HSCs) and CMPs and common lymphoid progenitors (CLPs). The Gata1^low mutation affects cells at the restriction point between CMPs and MEPs and MCPs (this report). On the other hand, the Gata1^null mutation is associated with development of thrombopoietin-dependent cell lines and has been suggested to affect the restriction point between MEPs and CFU-MK_day3 and CFU-E.⁵⁹  Modified from Stachura et al⁵⁹  with permission.