A CONDITIONALLY IMMORTALIZED GLIAL-CELL LINE THAT EXPRESSES MATURE MYELIN PROTEINS AND FUNCTIONAL GABA(A) RECEPTORS

We have isolated and characterized a conditionally immortalized glial cell line that expresses mature myelin proteins, as well as functional GABA(A) receptors, Glial cells were isolated from postnatal day 1 H-2 Kb-tsA58 transgenic mice that contain the temperature-sensitive SV40 l arge T antigen oncogene under the control of an interferon-gamma-induc ible promoter. A clonal line was isolated that grew rapidly under perm issive conditions (33 degrees C in the presence of interferon-gamma), but not under nonpermissive conditions (37 degrees C in the absence of interferon-gamma), Cells expressed mRNAs of mature myelin proteins (m yelin basic proteins and proteolipid protein) when grown under either permissive or nonpermissive conditions, but myelin basic proteins were detected only when cells were maintained at 37 degrees C. GABA induce d an increase in intracellular calcium concentration, indicating the p resence of functional receptors for this transmitter, Characterization of the GABA-evoked calcium response and whole-cell currents indicated that these responses were mediated by GABA(A) receptors, Reverse tran scription-polymerase chain reaction revealed differential expression o f mRNAs for specific GABA(A) receptor subunits. Messages for the alpha 2, alpha 4, beta 1, and delta subunits were readily detected by rever se transcription-polymerase chain reaction, whereas messages for the a lpha 1, alpha 3, alpha 5, alpha 6, beta 2, beta 3, and gamma 1-3 subun its were not, As this cell line can be easily propagated and different iated, it should provide a valuable tool in studying not only the deve lopment of oligodendroglia, but also the function of their transmitter receptors and myelin proteins.