Neural regulation of gene expression by an acetylcholine receptor promoter in muscle of transgenic mice.

Motor neurons regulate the quantity and distribution of acetylcholine receptors (AChR) in the muscles they innervate. Here, we report that an AChR alpha subunit gene fragment contains cis-acting regulatory sequences that confer neural regulation as well as tissue-specific regulation of transcription. An 850 bp fragment from the 5' end of the chicken AChR alpha gene fused to the reporter gene, chloramphenicol acetyltransferase (CAT), has been introduced into the genomes of several lines of transgenic mice. Expression of CAT enzyme activity in these mice is tissue-specific; the onset of expression in embryonic muscle correlates well with that of many other muscle-specific proteins. Most importantly, CAT enzyme is down-regulated 100-fold soon after birth, an effect that can be completely reversed by denervation.