O papel modulador do gene AIRE - capes

MANUSCRITOAbstractThe expression of peripheral tissue antigens (PTAs) in the thymus bymedullary thymic epithelial cells (mTECs) is essential for the central selftoleranceof T cells. Due to heterogeneity of autoantigen representation thisphenomenon has been termed promiscuous gene expression (PGE), inwhich the autoimmune regulator (Aire) gene plays a role as maintranscriptional activator on a large set of Aire-dependent PTAs. Aire proteinis able in binding to specific DNA sequence motifs and plays a role as adirect regulator. Here we used the cDNA microarray method to access PGEin murine CD80 + 3.10 mTEC cell strain cultured in vitro. Hierarchicalclustering of the data allowed observation that PTA genes were differentiallyexpressed being possible to found those induced or repressed. To furtherinvestigate the control of PGE, we hypothesize that PTA genes establishnetworks, reflecting the existence of a feedback-like control of thetranscriptional levels. Aire in this case plays a role as upstream modulator.To test this hypothesis, initially we silenced Aire by gene knockdown (RNAinterference) in 3.10 mTEC cells. Hierarchical clustering of cDNA microarraydata showed a set of Aire-dependent PTA genes, which weredownregulated after Aire silencing. Gene networks reconstructed from thesedata allowed the identification of a gene node (Gucy2d) establishing positiveregulation upon downstream genes in normal mTECs. Nevertheless, undersilencing of Aire, Gucy2d has become a repressor on PTA genes. Thesefindings evidentiate that genes featured in PGE are connected in network, agene node may act as intermediate in their control and that Aire in PGEnetwork plays a role as an upstream regulator.203