Background：

Transcription factor playing an essential role to promote self-tolerance in the thymus by regulating the expression of a wide array of self-antigens that have the commonality of being tissue-restricted in their expression pattern in the periphery， called tissue restricted antigens (TRA). Binds to G-doublets in an A/T-rich environment; the preferred motif is a tandem repeat of 5’-ATTGGTTA-3’ combined with a 5’-TTATTA-3’ box. Binds to nucleosomes. Binds to chromatin and interacts selectively with histone H3 that is not methylated at ’Lys-4’， not phosphorylated at ’Thr-3’ and not methylated at ’Arg-2’. Functions as a sensor of histone H3 modifications that are important for the epigenetic regulation of gene expression. Mainly expressed by medullary thymic epithelial cells (mTECs)， induces the expression of thousands of tissue-restricted proteins， which are presented on major histocompatibility complex class I (MHC-I) and MHC-II molecules to developing T-cells percolating through the t