Globin synthesis in mouse erythroleukemia cells in vitro: A switch in β chains due to inducing agent

Friend erythroleukemia cells, originally derived from DBA/2 mice, differentiate when cultured with inducing agents. Studies of the different effects of inducing agents on clone 745 have revealed that both dimethyl sulfoxide (DMSO) and hemin produce benzidine-positive cells. Butyric acid produced mature but benzidine-negative cells in this clone. All agents induced globin synthesis above the 0.1% of protein synthesis found in uninduced cells. DMSO induction stimulated globin synthesis 9%, hemin 2%, and butyric acid 3%. Total β/α ratios were approximately unity with all agents. Although the inducing agents all stimulated total globin synthesis in Friend cells, the relative rates of synthesis of the two mouse β chains were affected differently by the various agents. Hemin markedly increased the proportion of β minor. For example, DBA/2 mouse reticulocytes synthesized 20% β minor and 80% β major. DMSO induction of clone 745 caused 20%-33% synthesis of β minor, and butyric acid 30%-37% β minor. In contrast, hemin increased the proportion of β minor to 64%-69%. Thus the Friend erythroleukemia cell system provides an in vitro approach to the study of the regulation of globin-chain switching.