Distinct spatiotemporal expression of mRNAs for the PSD-95/SAP90 protein family in the mouse brain

PSD-95 (SAP90), SAP102. and Chapsyn-110 (PSD-93) are members of the membran e-associated guanylate kinase family, and interact with N-methyl-D-aspartat e (NMDA) receptor NR2A (GluR epsilon 1) and NR2B (GluR epsilon 2) subunits and with Shaker-type Kt channel subunits to cluster into a channel complex. In the present study, we examined their expression in developing and adult mouse brains by in situ hybridization with antisense oligonucleotide probe s. PSD-95 and SAP102 mRNAs were prominently expressed at embryonic day 13 ( E13) in the mantle zone of various brain regions, where NMDA receptor NR2B subunit mRNA is expressed at high levels, In the early postnatal period whe n active synaptogenesis takes place, both mRNAs became elevated and concent rated in the telencephalon and cerebellar granular layer, where NR2A and/or NR2B subunit mRNAs are abundantly expressed. Chapsyn-110 mRNA was, though at low levels, found over the mantle zone of embryonic brains, and the leve l was progressively increased in the telencephalon starting at perinatal st ages. The spatial and temporal correlations in the brain in vivo suggest th at the PSD-95/SAP90 protein family can interact with NMDA receptor subunits to cluster them into channel complex at both synaptic and non-synaptic sit es before, during and after synaptogenic stages. (C) 1999 Published by Else vier Science Ireland Ltd. All rights reserved.