Truncated form of pro-acetycholine receptor-inducing activity (ARIA) induces AChR α-subunit but not AChE transcripts in cultured chick myotubes

Abstract

Acetylcholine receptor-inducing activity (ARIA) is a glycoprotein initially purified from chick brain based on its ability to increase the synthesis of acetylcholine receptor (AChR). We used reverse transcription-polymerase chain reaction (RT PCR) to obtain a partial pro-ARIA cDNA clone from methonine-1 to serine-358 including the full functional sequence of ARIA. Northern blot analysis of mRNAs from the embryonic chick brain and muscle showed a transcript with a size of ∼7.5 kb. The cloned cDNA was subcloned into an eukaryotic expression vector and stably transfected into human embryonic kidney 293 cells. The conditioned medium of the transfected cells was found to increase the level of transcript encoding for the α-subunit of AChR by ∼4.4-fold, but not for acetylcholinesterase (ACNE), in the cultured chick myotubes.