Ultrastructural characterization of a mouse melanoma cell line, a mouse fibroblastic cell line, and hybrids between them.

This report describes a transmission electron microscopic study on hybrids between subhexaploid mouse melanoma cells and subtetraploid mouse fibroblasts. The melanoma cell line was heterogeneous in terms of pigment production, but all cells contained melanosomes, although in different stages of development. Characteristic features of the fibroblasts included the cytoskeleton, endocytic vesicles, and occurrence of dilated cisternae of granular endoplasmic reticulum. Despite the gene dosage in favour of the melanoma parent cell, the hybrids were devoid of melanosomes, and their phenotype was typically fibroblastic in character.