2 NEURONAL CELL-LINES EXPRESSING THE MYELIN BASIC-PROTEIN GENE DISPLAY DIFFERENCES IN THEIR IN-VITRO SURVIVAL AND IN THEIR RESPONSE TO GLIA

We have generated two conditionally immortalized neuronal cell lines f rom primary cultures of embryonic day 13 (E13) and postmitotic (postna tal day 0; PO) cortical neurons transformed with the temperature-sensi tive SV-40 large-T antigen. Two clonal cell lines (CN1.4 from E13 cult ures and SJ3.6 from PO cultures) were isolated and stable maintained i n vitro. Both cell lines expressed a number of neuronal markers such a s the neurofilaments, glutamic acid decarboxylase 67, neuron-specific enolase, and the BG21 isoform of the myelin basic protein gene. At 34 degrees C, the CN1.4 cell line had elaborated short processes, whereas the SJ3.6 cell line produced long processes that formed a delicate ne twork, When these cell lines were cultured at 39 degrees C, some of th e cellular processes grew longer, adopting a more mature neuronal morp hology, Interestingly, at 39 degrees C, the in vitro survival of these cell lines differed significantly. Whereas the survival of CN1.4 cell line was greatly unaffected, SJ3.6 cells died soon after they were cu ltured at 39 degrees C, The cell death of SJ3.6 cells was accompanied by fragmentation and condensation of DNA in their nuclei, indicative o f an apoptotic event. Under these conditions, SJ3.6 showed an upregula tion of the p75 receptor. When this cell line was cocultured with olig odendrocytes, astrocytes, or glial conditioned media (GCM), there was a marked increase in survival. In contrast, little effect of glial cel ls or GCM was observed on the CN1.4 cell line. These lines appear to b e useful models to study neuronal-glial interactions in addition to ne uronal cell death and the effects of glial factors that promote the su rvival of neurons. (C) 1998 Wiley-Liss, Inc.