Murine stem cell factor stimulates erythropoietic differentiation of ventral mesoderm in Xenopus gastrula embryo.

We have reported that the animal pole cells stimulate the ventral mesoderm of early gastrula Xenopus embryo (stage 10) to differentiate into erythrocytes. To determine the molecular mechanism(s) involved in the stimulatory effect of the animal pole, ventral mesoderm explants were cultured in the presence of various defined cellular factors. In this study, we report that murine stem cell factor (SCF) stimulates globin expression at the optimum dose of 10 ng/ml. Globin expression was observed from the ventral mesoderm explants treated with SCF, but not from the dorsal mesoderm and the animal pole explants. Morphological studies of the ventral mesoderm treated with SCF showed that only a certain population of the ventral mesoderm differentiates into erythrocytes. On the other hand, coculture of ventral mesoderm and animal pole revealed the differentiation of the entire structures into mesenchyme, blood cells, and the overlying epidermis. These data suggest that SCF may play a role in the stimulation of erythrocytic differentiation, but the effect of the animal pole cells cannot be replaced with that of SCF.