Changes in surface glycoconjugates in adhesion-defective variants of P19 embryonal carcinoma cells

Embryonal carcinoma cells defective in their ability to adhere to tissue culture dishes were isolated from mutagenized P19X1 and P19S1801A1 cells. Three independently isolated variants were analyzed for their morphology, surface properties and ability to differentiate in vitro. Two of the mutant cell lines expressed similar amounts of stage-specific embryonic antigens TEC-1, TEC-4 and Thy-1 as parental cells, whereas all three showed significant reduction in the expression of uvomorulin as determined by a direct radioantibody binding assay. Variant cells exhibited a decrease in their ability to aggregate in media with or without CA2+ and were unable to form compact aggregates when cultured for two days in complete culture media. In the presence of retinoic acid variant cells formed aggregates which exhibited significantly lower frequency neuron formation after transfer to tissue culture dishes. The combined data indicate that the adhesion-defective phenotype of P19-derived cells is in part the result of a reduced surface expression of uvomorulin.