Erythroid Ce11 Differentiation

The study of erythroid cell difierentiation is pertinent to the study of human leukemia from two points of view. First, since a common stem cell gives rise to both erythroid and myeloid cells, it is not unexpected that disorders of myeloid cell proliferation and differentiation should be occasionally associated with abnormalities of erythroid cell differentiation. In fact in many cases of human leukemia, there are abnormalities of erythroid cells. Secondly, the study of erythroid cell differentiation can serve as an experimental model for the study of normal and abnormal gene expression, a topic of vital importance to the understanding of the etiology and pathogenesis of human leukemia. The erythoid cell provides a number of advantages as a model System for the study of the control of gene expression. This highly specialized cell devotes approximately 95 010 of its protein synthesis to the production of one protein, hemoglobin, and therefore only a limited number of the cell's genes are expressed. In addition, a number of biochemical techniques are currently available for the isolation, characterization and quantitation of globin messenger RNA (mRNA), the necessary intermediary between $obin gene expression and globin chain synthesis. Erythroid cell differentiation can be considered from two points of view: 1) differences between fetal and adult mature red blood cells; and 2) differences between erythroid cells at different stages of morphologic maturation. We will discuss first the abnormalities of red cell differentiation, mainly the emergence of fetal erythropoiesis, which can occur during the Course of various human leukemias. Then we will discuss experimental studies on the quantitation of heme synthesis, globin synthesis and globin messenger RNA content in murine erythroid cells at different stages of maturation.