Aire和Fezf2是被鉴定的仅有的两个能够直接调控胸腺髓质组织限制性抗原表达，进而调控中枢免疫耐受的基因。但仍有大量不依赖这两个因子的组织限制性抗原表达，且尚未鉴定出相应的调控基因，也不清楚Aire和Fezf2这两个被认为相互独立的关键因子之间的转录调控关系。我们前期研究发现，被认为仅在神经内分泌细胞表达的Insm1基因在胸腺髓质细胞中与Aire/Fezf2共表达，Insm1突变导致Aire、Fezf2和一些依赖与不依赖这两个因子的组织限制性抗原表达水平降低；移植该突变型胸腺后宿主胰岛发生淋巴细胞浸润。本课题拟采用Insm1突变小鼠，探索Insm1直接调控的组织限制性抗原亚群，研究Insm1调控Aire/Fezf2和组织限制性抗原表达的分子机制，分析突变导致的自身免疫表型。从而鉴定Insm1为新型中枢免疫耐受调控基因，揭示髓质细胞转录调控新机制，为解释人类自身免疫性疾病提供新的分子基础。

Promiscuous gene expression results in the peripheral tissue-restricted-antigens (TRAs) presentation in medullary thymic epithelial cells (mTECs), which plays an essential role in establishing of central self-tolerance. Aire and Fezf2 are so far identified the only two unique transcription factors that directly regulate TRAs expression and autoimmunity. Aire and Fezf2 regulate different subsets of TRAs and were regulated by non-identical upstream cell signaling. The transcriptional regulation of Aire is intensively studied. However, how transcriptional regulation of Fezf2 expression and what regulatory interactions occur between Aire and Fezf2 in the thymus are unknown. In addition, numerous TRAs exist that exhibit expression independent of Aire or Fezf2, this state-of-affairs raises the possibility that other transcription factors are involved in TRAs regulation. Our preliminary data showed that Insulinoma-associated protein 1 (Insm1) fulfills such regulatory function. Particularly, we found that Insm1 co-expressed with Aire and Fezf2 in mTEC, down-regulation of Aire, Fezf2 and TRAs were observed in Insm1 mutated thymus. We found the lymphocytes infiltration in pancreas of the nude mice transplanted with the Insm1 mutant thymus. In this project, we will systematically identify the TRAs that regulated by Insm1, and the molecular mechanisms of Insm1 function in the regulation of Aire, Fezf2 and TRAs. In addition, we will further investigate the autoimmune phenotypes in nude mice transplanted with the Insm1 mutant thymus and in thymic specific Insm1 mutant mice. Our study will provide the first evidence for the co-regulation of Aire and Fezf2 at the transcriptional level regulated by Insm1. Insm1, a neuroendocrine specific factor, will be identified as the novel factor that directly regulates a set of TRAs expression and autoimmunity. Thus, our study will provide the novel molecular basis for central tolerance and rare autoimmune diseases.