Persistence, suppression and re-expression of pigment formation in somatic cell hybrids between mouse melanoma cells and non-melanoma cells.

Pigmented subtetraploid subhexaploid mouse melanoma cells were fused with a range of different cell types. Expression of pigment formation appeared to be dependent on the phenotype of the non-melanoma parent cell, so that hybrids with lymphoid cells or chick embryo erythrocytes produced pigment, but hybrids between fibroblasts or epithelial rat hepatoma cells did not. The results were independent of gene dosage of either parent cell. gamma-irradiation of suppressing partner cells prior to fusion caused progressive increase in pigmentation with increasing dose of radiation. Cybrids between cytoplasts of suppressing fibroblasts and melanoma cells were pigmented.