Down-modulation of c-kit mRNA and protein expression by erythroid differentiation factor/activin A.

We examined the effects of erythroid differentiation factor (EDF)/activin A on the expression of c-kit mRNA and protein in murine erythroleukemia (MEL) cells. EDF/activin A induced MEL cells to benzidine positive cells. Northern blot analysis showed that the c-kit mRNA expression was reduced synchronously with increase of beta-globin and uroporphyrinogen decarboxylase gene expression during EDF/activin A induced erythroid differentiation. Scatchard analysis indicated that the cell surface receptor number was reduced without change of affinity during differentiation. Our results suggest that EDF/activin A may act as a natural regulator of erythropoiesis with modulation of c-kit gene expression.