Project description:Medullary thymic epithelial cells play essential role for induction of central self-tolerance. This functional capacity is mediated through a phenomenon known as promiscuous gene expression (pGE) of various tissue-restricted antigen (TRA) genes. pGE was previously shown to be mediated by a single factor called the Autoimmune regulator (Aire), which is specically expressed by mTECs. The aim of this study was to analyze the impact of deacetylase Sirtuin1, which is also highly expressed by mTECs, on mTEC gene expression profile and compare it with the impact of Aire. We used Affymetrix mouse 1ST arrays to analyze the impact of the Sirt1 gene on the gene expression profile of MHC-II high medullary thymic epithelial cells
Project description:Aire is a transcriptional regulator that induces promiscuous expression of thousands of tissue-restricted antigen (TRA) genes in medullary thymic epithelial cells (mTECs). While the target genes of Aire are well characterized, the transcriptional programs regulating its own expression remain elusive. We used Affymetrix microarrays to analyze the gene expression patterns of Aire expressing cells (mature mTECs and Thymic B cells) and compared them to control counterparts, namely immature mTECs, cortical Thymic epithelial cells and splenic B cells of tissue-restricted antigen (TRA) genes in medullary thymic epithelial cells (mTECs). While the target genes of Aire are well characterized, the transcriptional programs regulating its own expression remain elusive. We used Affymetrix microarrays to analyze the gene expression patterns of Aire expressing cells (mature mTECs and Thymic B cells) and compared them to control counterparts, namely immature mTECs, cortical Thymic epithelial cells and splenic B cells.
Project description:Medullary thymic epithelial cells play essential role for induction of central self-tolerance. This functional capacity is mediated through a phenomenon known as promiscuous gene expression (pGE) of various tissue-restricted antigen (TRA) genes. pGE was previously shown to be mediated by a single factor called the Autoimmune regulator (Aire), which is specically expressed by mTECs. The aim of this study was to analyze the impact of deacetylase Sirtuin1, which is also highly expressed by mTECs, on mTEC gene expression profile and compare it with the impact of Aire. We used Affymetrix mouse 1ST arrays to analyze the impact of the Sirt1 gene on the gene expression profile of MHC-II high medullary thymic epithelial cells Mature MHC-II high mTECs were flow-sorted from thymi isolated from B6.Sirt1fl/fl, B6.Sirt1fl/flFoxn1-Cre and B6.Aire–/– 6weeks old mice. Typically, 3 mice were pooled to obtain 30-60 thousand sorted mTECs, which were then analyzed by gene expression profiling. Specifically, total RNA was extracted from ~30,000 pooled sorted cells using Trizol. Purified total RNA was then amplified using the MessageAmp RNA kit (Ambion). Biotinylated cRNA was then hybridized to Affymetrix Mouse Gene 1-ST arrays by the genomics core at the Weizmann Institute
Project description:To understand the role of Jmjd3 in medullary thymic epithelial cells (mTECs) function and development, Jmjd3 was conditionally deleted in thymic epithelial cells. At the age of 4 weeks, mTECs were sorted by flow cytometry and RNA-seq was performed to identify the genes targeted by Jmjd3 for repression.
Project description:Thymic epithelial cells govern thymic T lymphocyte differentiation and selection. Medullary TECs (mTECs) facilitate the negative selection of self-reactive thymocytes and the differentiation of FOXP3+ regulatory T cells. Medullary TECs are also distinctive for their “promiscuous” gene expression, transcribing thousands of peripheral tissue genes (PTG) that are otherwise only expressed highly in one or two other organs. Much of this PTG expression by mTECs is controlled by the autoimmune regulator, AIRE. To probe the mechanism by which KAT7 promotes AIRE function, we performed ATAC-seq to compare chromatin accessibility in MHCII-high medullary thymic epithelial cells from Kat7-knockout and wildtype mice.
Project description:Autoimmune regulator (Aire) is a unique transcriptional regulator that induces promiscuous expression of thousands of tissue-restricted antigens (TRAs) in medullary thymic epithelial cells (mTECs), a step critical for induction of immunological self-tolerance. Although several recent studies provided very important molecular insights into how Aire operates, a more comprehensive understanding of this process still remains elusive. Here we demonstrate that a lysine deacetylase Sirtuin-1 (Sirt1) is predominantly expressed in mature Aire+ mTECs, where it is required for expression of Aire-dependent TRA genes and a subsequent induction of immunological self-tolerance. Our study elucidates a previously unknown molecular mechanism for Aire-mediated transcriptional regulation and uncovers a unique functional role for Sirt1 in preventing organ-specific autoimmunity.
Project description:Aire is a transcriptional regulator that induces promiscuous expression of thousands of tissue-restricted antigen (TRA) genes in medullary thymic epithelial cells (mTECs). While the target genes of Aire are well characterized, the transcriptional programs regulating its own expression remain elusive. We used Affymetrix microarrays to analyze the gene expression patterns of Aire expressing cells (mature mTECs and Thymic B cells) and compared them to control counterparts, namely immature mTECs, cortical Thymic epithelial cells and splenic B cells of tissue-restricted antigen (TRA) genes in medullary thymic epithelial cells (mTECs). While the target genes of Aire are well characterized, the transcriptional programs regulating its own expression remain elusive. We’ve used Assay for transposase-accessible chromatin using sequencing (ATAC-Seq) on the different thymic epithelial cell populations to assess chromatin accessibility around the Aire locus in these cells. Moreover, we’ve used the indexing-first chromatin immunoprecipitation (iChIP) technique to assess the occupancy of the Irf8 transcription factor in the Aire locus
Project description:Aire is a transcriptional regulator that induces promiscuous expression of thousands of tissue-restricted antigen (TRA) genes in medullary thymic epithelial cells (mTECs). While the target genes of Aire are well characterized, the transcriptional programs regulating its own expression remain elusive. We used Affymetrix microarrays to analyze the gene expression patterns of Aire expressing cells (mature mTECs and Thymic B cells) and compared them to control counterparts, namely immature mTECs, cortical Thymic epithelial cells and splenic B cells of tissue-restricted antigen (TRA) genes in medullary thymic epithelial cells (mTECs). While the target genes of Aire are well characterized, the transcriptional programs regulating its own expression remain elusive. We’ve used Assay for transposase-accessible chromatin using sequencing (ATAC-Seq) on the different thymic epithelial cell populations to assess chromatin accessibility around the Aire locus in these cells. Moreover, we’ve used the indexing-first chromatin immunoprecipitation (iChIP) technique to assess the occupancy of the Irf8 transcription factor in the Aire locus
Project description:The oligo microarrays were used to determine mRNA expression profiles of medullary thymic epithelial cells (mTECs) isolated from thymus of pre-diabetic NOD mice.