APP EXPRESSION IN PRIMARY NEURONAL CELL-CULTURES FROM P6 MICE DURING IN-VITRO DIFFERENTIATION

Primary neuronal cell cultures from P6 mice were investigated in order to study amyloid protein precursor (APP) gene expression in different iating neurons. Cerebellar granule cells which strongly express APP 69 5 allowed the identification of three distinct isoforms of neuronal AP P 695. The high-molecular-weight form of APP 695 is sialylated. The ex pression pattern of neuronal APP 695 changes during in vitro different iation. Sialylated forms become more abundant upon longer cultivation time. The secreted forms of sialylated, neuronal APP 695 are shown to comigrate with APP isolated from cerebrospinal fluid. We suggest that the different sialylation states of APP 695 may reflect the modulation of cell-cell and cell-substrate interactions during in vitro differen tiation and regeneration.