DEVELOPMENTAL-CHANGES IN THE EXTENT OF RNA EDITING OF GLUTAMATE-RECEPTOR SUBUNIT GLUR5 IN RAT-BRAIN

The extent of RNA editing of the glutamate receptor subunit GluR5 mRNA was evaluated in the cortex, hippocampus and cerebellum of embryonic rat brains, aged 19 days, and adult brains, aged 2-3 months. RNA was i solated and transcribed into cDNA, which was used as template for ampl ifying a PCR product across the edited region of the GluR5 subunit. Qu antification of editing was performed by restriction digest of PCR pro ducts with BbvI and image analysis of bands obtained after electrophor esis. The extent of editing was significantly lower in the embryonic s tate as compared to the adult state. These differences were most prono unced in the cerebellum where the extent of editing amounted to 27+/-8 % and 78+/-2% in the embryonic and adult state, respectively (P < 0.00 1). Since expression of GluR5 is relatively high in brain areas of neu ronal differentiation and synapse formation it is concluded that un-ed ited GluR5 may play a role in the development of the nervous system.