Project description:In mice lacking the heme exporter, FLVCR, differentiation fails at the CFU-E/proerythroblast stage from excessive heme and reactive oxygen species. We show that Flvcr1-deleted CFU-E/proerythroblasts have low GATA1 mRNA and GATA1-target gene mRNAs along with increased ribosomal protein mRNAs as a direct result of increased heme. Thus heme increases ribosomal protein transcription when globin production needs to be increased, and when heme is excessive, GATA1 is reduced allowing for normal termination of erythroid differentiation. This demonstrates that heme and GATA1 are co-master regulators of erythroid differentiation.
Project description:In mice lacking the heme exporter, FLVCR, differentiation fails at the CFU-E/proerythroblast stage from excessive heme and reactive oxygen species. We show that Flvcr1-deleted CFU-E/proerythroblasts have low GATA1 mRNA and GATA1-target gene mRNAs along with increased ribosomal protein mRNAs as a direct result of increased heme. Thus heme increases ribosomal protein transcription when globin production needs to be increased, and when heme is excessive, GATA1 is reduced allowing for normal termination of erythroid differentiation. This demonstrates that heme and GATA1 are co-master regulators of erythroid differentiation.
Project description:FAM122A is a highly conserved housekeeping gene, but its physiological and pathophysiological roles remain greatly elusive. Based on the fact that FAM122A is highly expressed in human CD71+ early erythroid cells, herein we report that FAM122A is downregulated during erythroid differentiation, while its overexpression significantly inhibits erythrocytic differentiation in primary human hematopoietic progenitor cells and erythroleukemia cells. Mechanistically, FAM122A directly interacts with the C-terminal zinc finger domain of GATA1, a critical transcriptional factor for erythropoiesis, and reduces GATA1 chromatin occupancy on the promoters of its target genes, thus resulting in the decrease of GATA1 transcriptional activity. The public datasets show that FAM122A is abnormally upregulated in patients with ?-thalassemia. Collectively, our results demonstrate that FAM122A plays an inhibitory role in the regulation of erythroid differentiation, and it would be a potentially therapeutic target for GATA1-related dyserythropoiesis or an important regulator for amplifying erythroid cells ex vivo.
