Expression and alternative splicing of the mouse autoimmune regulator gene (Aire)

AIRE, the gene responsible for the autoimmune polyglandular syndrome type 1 (APS1) or APECED, may act as a transcription factor according to its predicated protein structure. Here we demonstrate the low expression level of the mouse Aire gene as it is undetectable by Northern blot analyses. However, RT-PCR analyses revealed expression of Aire in mouse thymus, ovary, lung, testis, kidney and adrenal gland. Barely detectable level of RT-PCR product was also found in thyroid gland and heart but no amplification was detected in pancreas, spleen and liver. Competitive RT-PCR assays demonstrated highest expression level of Aire mRNA in thymus. In addition to the complete cDNA (Aire or Aire-1a), we identified 11 alternative splicing forms (designated as Aire-1b, Aire-1c, Aire-1d, Aire-2a, Aire-2b, Aire-2c, Aire-2d, Aire-3a, Aire-3b, Aire-3c and Aire-3d). These forms result from combinations of four alternative splicing units (exon 10, exon 11, 12 bp in exon 6 and 3 bp in exon 8). The relative abundance of these splicing forms was also determined.