DISTRIBUTION OF ZINC METALLOTHIONEIN-I MESSENGER-RNA IN RAT-BRAIN USING IN-SITU HYBRIDIZATION

Metallothionein (MT) isoforms I and II were first identified and chara cterized in our laboratories in several regions of brain, in hippocamp al neurons in primary culture, and in retinoblastoma and neuroblastoma cell lines. In this study, by having employed the MT-I cDNA as a prob e, we sought to gain additional insight about the function of MT by di scerning the regional distribution of its mRNA. Northern blot analyses of brain mRNA revealed that the administration of zinc enhanced drama tically MT-I mRNA (570 bp). The in situ hybridization study revealed t hat MT-I mRNA was located in several areas of brain, with the highest concentrations found in the cerebellum, hippocampus, and ventricles. T he results of these studies are interpreted to suggest that zinc enhan ces the synthesis of MT mRNA and MT in turn may participate in zinc as sociated functions in neurons.