From oocytes to neurones and from Drosophila to vertebrates, intracellular targeting and localization of molecules contribute to regulation of gene expression.
In the past year I performed light (lm) and electron (em) microscopic nonisotopic in situ hybridization (ISH) studies to investigate the regional and subcellular distribution of glycine receptor (GlyR) subunit mRNAs in rat and mouse CNS neurones. I found that alpha and beta subunit mRNAs have somatodendritic and somatic localizations, respectively. Studies of other nonneuronal cell types suggest that the differential intracellular distribution of mRNAs depends on signal sequences in the 3'untranslated region (UTR). I will construct, express in neuronal cell cultures, and visualize by lm and em ISH tagged-chimeric GlyR subunit cDNAs, containing or lacking normal or mutated 3'UTR. This will allow identification of the mRNA targeting sequences which distinguish and determine, by interaction with the trafficking machinery, the different intracellular distributions of GlyR subunit transcripts.