EXPRESSION OF ALPHA-3-NEURONAL, ALPHA-5-NEURONAL AND BETA-4-NEURONAL ACETYLCHOLINE-RECEPTOR SUBUNIT TRANSCRIPTS IN NORMAL AND MYASTHENIA-GRAVIS THYMUS - IDENTIFICATION OF THYMOCYTES EXPRESSING THE ALPHA-3 TRANSCRIPTS

We used amplification of reverse transcribed RNA to investigate the th ymic transcription of genes encoding for subunits of neuronal acetylch oline receptors (AcChR). All thymic tissues investigated, which includ e normal thymi, myasthenic hypertrophic thymi, and both myasthenic and nonmyasthenic thymomas, express transcripts encoding for the alpha-3, the alpha-5, and the beta-4 subunits of AcChR. The thymic transcripti on of at least three different genes encoding for neuronal AcChR subun its suggests there is expression of neuronal AcChR in thymus. Amplific ation of reverse transcribed RNA and Northern blotting of thymic and p eripheral immunocytes showed that thymocytes but not peripheral lympho cytes express alpha-3 AcChR subunit transcripts. This finding suggests that within the T cell lineage there is transcriptional regulation of the alpha-3 AcChR gene.