Dynamic regulation of PU.1 expression in multipotent hematopoietic progenitors

Abstract

PU.1 is an Ets family transcription factor that is essential for fetal liver hematopoiesis. We have generated a PU.1gfp reporter strain that allowed us to examine the expression of PU.1 in all hematopoietic cell lineages and their early progenitors. Within the bone marrow progenitor compartment, PU.1 is highly expressed in the hematopoietic stem cell, the common lymphoid progenitor, and a proportion of common myeloid progenitors (CMPs). Based on Flt3 and PU.1 expression, the CMP could be divided into three subpopulations, Flt3+ PU.1hi, Flt3- PU.1hi, and Flt3- PU.1lo CMPs. Colony-forming assays and in vivo lineage reconstitution demonstrated that the Flt3+ PU.1hi and Flt3- PU.1hi CMPs were ef..