NEURONAL-ACTIVITY INDUCTION OF THE STATHMIN-LIKE GENE RB3 IN THE RAT HIPPOCAMPUS - POSSIBLE ROLE IN NEURONAL PLASTICITY

Synaptic activity induces a rapid transcriptional response that is ess ential for the establishment of long-term neuronal plasticity. Using a differential cloning technique, we have identified a gene induced by seizure activity in the brain as RB3. RB3 is a recently cloned gene be longing to the stathmin family of phosphoproteins. Like SCG10, RB3 is brain-specific, although in situ hybridization results show that the e xpression of RB3 is more ubiquitous than is that of SCG10. Using genom ic DNA sequencing, we show that the 27 amino acid sequence unique to t he RB3 '' transcript is encoded by an alternatively spliced exon, exon 2'. Using a peptide antibody raised against exon 2' to detect RB3 '' and an anti-flag antibody to detect an epitope-tagged version of RB3, we show that both proteins are localized to the Golgi apparatus of tra nsfected COS7 cells. Of particular interest, RB3 mRNA, but not SCG10 m RNA, is rapidly induced in the dentate gyrus granule layer of the hipp ocampus after electrically induced seizure activity as well as stimuli leading to long-term potentiation (LTP). In addition, RB3 mRNA is ind uced in pheochromocytoma (PC12) cells treated with 250 ng/ml NGF. Thes e results suggest that RB3 may play a role in activity-induced neurona l plasticity and neuronal differentiation.