Accumulation of 210 kDa microtubule-interacting protein in differentiatingP19 embryonal carcinoma cells

The MA-01 antigen, a thermolabile 210 kDa microtubule-interacting protein, is present in P19 embryonal carcinoma cells on microtubular structures as w ell as in cytosol, After aggregation of the cells and subsequent incubation with all-trans-retinoic acid (RA), the level of MA-01 expression increased approximately 10 times during 15 days. The increase started after 2 days o f incubation with RA and preceded the appearance of neuron-specific tubulin beta III, MAP2C and neurofilaments. Such elevated expression of MA-OI anti gen was not detected in P19 cells treated with dimethylsulfoxide. These dat a indicate that enhanced expression of MA-01 antigen is one of the earliest events occurring in P19 cells during neuronal differentiation. (C) 2000 Fe deration of European Biochemical Societies.