The transcription co-factor FOG1 interacts with the chromatin remodeling complex NuRD to mediate gene activation and gene repression during hematopoiesis. We have generated mice with a targeted mutation in the endogenous Fog1 locus that results in an N-ternimal mutation in FOG1 that disrupts the interaction with NuRD. We used gene expression microarrays to explore the global transcriptional programs regulated by FOG1 and NuRD in megakaryocyte-erythroid progenitors (MEP) to aid in understanding its role during hematopoiesis. Flow cytometry was used to isolate Megakaryocyte-Erythroid progenitors (MEP) from murine bone marrow. MEP were identified as Lineage neg, kit pos, Sca1 neg, CD34 neg, FcgrII/III low cells.