Growth factor independence 1b (Gfi1b) is required for erythroid cell maturation and regulates embryonic globin expression [Mouse430_2]

Growth factor independence 1b (Gfi1b) is a DNA binding repressor of transcription with vital functions in hematopoiesis. Gfi1b-null embryos die at midgestation very likely due to defects in erythro- and megakaryopoiesis. To analyze the full functionality of Gfi1b in erythropoiesis, we used conditionally deficient mice that harbor floxed Gfi1b alleles and the Mx-Cre transgene inducible by pIpC treatment. We used bone marow cells from 12 weeks old wild type C57BL/6 mice or conditional Gfi1b knock-out mice, both carrying the Mx-cre transgene induced by five treatments with pIpC (500µg each) every other day and sacrificed 42 days after the first injection. Ter119 positive erythroid cells were isolated by flow cytometry and RNA from these cells was isolated using the Trizol procedure according to the manufacturers instructions for gene expression analysis on Affymetrix MOE_430 2.0 expression arrays (GPL 1261) We used microarray-based gene expression profiling to analyze the effect of loss of Gfi1b expression in Ter119 positive erythroid cells from mouse bone marrow.