Chapter 6 MicroRNA and Erythroid Differentiation

MicroRNAs (miRNAs) regulate diverse cellular functions by acting as sequence-specific regulators of gene expression. We have investigated miRNA expression profiles in erythroid cells at different stages of maturation and the regulation of erythroid differentiation by specific miRNAs. We found that more than one hundred miRNAs were expressed in erythroid cells. The majority of them showed changes in their expression levels during erythroid differentiation. Further analysis revealed that the overall miRNA expression levels are increased in more mature erythroid cells compared with less mature erythroid cells. Among the miRNAs that are expressed in erythroid cells, miR-451 was most significantly upregulated during erythroid maturation. Functional studies using gain of func- tion and loss of function approaches showed that miR-451 is associated with both human and mouse erythroid maturation. In conclusion, dynamic changes in miRNA expression occurred during erythroid differentiation, with an overall increase in the levels of miRNAs upon terminal differentiation of erythroid cells. MiR-451 may play a role in promoting erythroid differentiation.