Nerve-cell-specific proteins in teratocarcinoma-derived neuroblastomas and embryonic brain.

Neural differentiation was analyzed by two-dimensional gel electrophoresis in two parallel systems: in teratocarcinoma-derived tumors that became determined to the formation of nerve-like cells and in developing brain of the early mouse embryo. The comparative analysis revealed four putative nerve-specific proteins (NSP) with Mr of 29K, 26K, 20K, and 16K, each of which was synthesized in both neurogenic tumors and during brain development but not in muscle tissue of developing limbs nor in undifferentiated cells of a pluripotential teratocarcinoma. NSP 29 and NSP 20 were found to be transiently expressed early in brain development at gestation day 8.5. At this stage, NSP 26 was barely detectable, but was synthesized at higher rates in brain tissue of day-12 and day-15 embryos. NSP 16 was present in brain tissue at all analyzed developmental stages.