Increased levels of acetylcholine receptor alpha-subunit mRNA in experimental autoimmune myasthenia gravis.

To gain insight into the regulatory mechanisms underlying the blockade and loss of acetylcholine receptor (AChR) in myasthenia, we have followed AChR alpha-subunit mRNA levels in leg muscles of myasthenic and normal rabbits and rats. Northern blots of RNA preparations from normal and myasthenic animals were hybridized with a mouse AChR alpha-subunit cDNA probe. Our experiments indicate a specific increase (4-7-fold) in the levels of alpha-subunit mRNA in animals with experimental autoimmune myasthenia gravis (EAMG), in comparison with control animals. Actin mRNA levels were essentially unchanged. Our results thus suggest that EAMG is accompanied by an increased level of AChR gene transcription.