INVOLVEMENT OF EXTRACELLULAR-MATRIX IN ACETYLCHOLINE-RECEPTOR EPSILON-SUBUNIT GENE-EXPRESSION AT THE RAT NEUROMUSCULAR-JUNCTION

During neuromuscular development, the nerve induces the expression of acetylcholine receptor (AChR)epsilon-subunit gene selectively in synap tic myonuclei. Here we show that even after elimination of neural effe cts by denervation, synaptic expression of epsilon-subunit transcripts is maintained for >4 months. In contrast, after damage of the extrace llular matrix (ECM) by treatment with proteolytic enzymes, epsilon-sub unit mRNA is significantly reduced within less than 1 day, indicating a role of ECM in the regulation of AChR subunit transcripts at the syn apse.