This chapter discusses the three features of induced Murine Erythroleukemia Cells (MELC) differentiation dealing with the regulation of expression of developmentally specific genes and the relationships between differentiation and the cell cycle. The three features includes: (1) studies concerning the mechanisms regulating the initiation of terminal cell division (commitment), which is a characteristic feature of the development of both normal and transformed erythroid cells; (2) the nature of mechanisms regulating the expression of differentiation-specific genes during induced differentiation; (3) studies on the relationships among the cell division cycle, Deoxyribonucleic acid (DNA) synthesis, globin gene replication, and induced cell differentiation. Expression of induced differentiation is accompanied by an acceleration of the transcription at the globin loci, and possibly by post-transcriptional modulation of globin mRNA accumulation, as well. Cells at the stage of erythroid cell development, represented by the transformed, differentiation-arrested MELC, acquire a unique DNA structure and chromatin configuration around the globin genes that distinguish them from other nonerythroid cells. Passage through G and early S phase of the cell cycle, in the presence of inducer, is critical for subsequent globin gene expression and may be important in establishing the chromatin reconfiguration required for gene expression.
