Post-transcriptional regulation of tubulin mRNA in developing rat brain.

The transcriptional activity of tubulin genes during synaptogenesis in developing rat brain has been examined by 'nuclear run off assay'. For both alpha and beta tubulin genes, the relative rates of transcription were found to be high during the early phase of synaptogenesis (postnatal days 1-5) and declined 20-50% by the end of synaptogenesis (postnatal days 15-20). Comparison of the developmental alterations in the rates of transcription of both alpha and beta tubulin mRNA with the level of polysomal tubulin mRNA shows that the age related decline (70-80%) in the level of polysomal tubulin mRNA during synaptogenesis is much too large compared to the 20-25% decline in their transcription rates suggesting that tubulin mRNA levels in developing rat brain are regulated post-transcriptionally.