Genomics based approach for allergic disorderand development of innovative therapeutic strategy

初始CD 4 T细胞分化成辅助性T细胞的两个主要亚群，Th 1和Th 2，其基于它们的非重叠细胞因子谱和免疫调节功能来定义。Th 1细胞分泌IFN-γ和TNF-α，并负责细胞介导的免疫和针对细胞内病原体的保护，而Th 2细胞产生IL-4、IL-5、IL-6、IL-10和IL-13，并介导体液免疫和针对蠕虫感染的保护。小鼠Th 2细胞因子基因座含有IL 4、IL 5、IL 13以及组成型表达的Rad 50和Kif 3a基因，并且基因座组成在哺乳动物中是很保守的。Th 2细胞因子的表达在遗传上受顺式作用调控元件处的转录允许和抑制染色质结构的调节，这已经通过检测DNaseI超敏（HS）位点和组蛋白修饰而被实验鉴定。在小鼠Th 2基因座中，IL 4转录受定位于保守序列1（HSS 1和HSS 2）的元件调节 关于我们 ），位于II 13和II 4之间，HS 0，位于II 4的5'区，HS 1，位于启动子区，HS 2和HS 3在第二外显子，HS 5a和HS 5，位于II 4的3'。Il 13基因座含有两个启动子区，HS 1和HS 2。HS 1是近端启动子HS 2上游的保守加塔-3应答元件（CGRE）。研究IL-4调控元件在小鼠与这些调控区域的种系缺失仍然留下开放的问题，是否每个元素调节IL-4转录或Th 2分化。我们的研究表明IL-4基因座中的HS 2是调节谱系特异性IL-4表达的关键加塔-3结合位点。HS 2的缺失显著损害了H3 K9/K14乙酰化的维持和Il 4基因座上H3 K4甲基化的开始，这两者都是转录允许性所需的，导致Il 4转录的缺乏。加塔-3过表达不能重建这些缺陷。我们发现，HS 2作为加塔-3介导的IL 4位点上的表观遗传修饰的特异性靶点，是不可或缺的增强子。因此，我们发现了加塔-3蛋白对Th 2细胞因子基因的一种新的调节作用。少

Naive CD4 T cells differentiate into two major subsets of helper T cells, Th1 and Th2, which are defined based on their non-overlapping cytokine profiles and immunoregulatory functions. Th1 cells secrete IFN-γ and TNF-α and are responsible for cell-mediated immunity and protection against intracellular pathogens, whereas Th2 cells produce IL-4, IL-5, IL-6, IL-10, and IL-13, and mediate humoral immunity and protection against helminthic infection. The mouse Th2 cytokine locus contains Il4, Il5, Il13, and the constitutively expressed Rad50 and Kif3a genes, and the locus composition is well conserved in mammals. Th2 cytokine expression is heritably regulated by transcriptionally permissive and repressive chromatin structure at cis-acting regulatory elements, which have been experimentally identified by the detection of DNaseI hypersensitive(HS) sites and histone modifications. In the mouse Th2 locus, Il4 transcription is regulated by elements that map to conserved sequence 1(HSS1 and HSS2 … More ), located between Il13 and Il4, HS0, located in the 5' region of Il4, HS1, located in the promoter region, HS2 and HS3 in the second exon, and HS5a and HS5, located 3' of Il4. The Il13 locus contains two promoter regions, HS1 and HS2. HS1 is the conserved GATA-3 response element(CGRE) upstream of the proximal promoter, HS2. Studies of IL-4 regulatory elements in mice with a germline deletion of these regulatory regions still leave open the question of whether each element regulates Il4 transcription or Th2 differentiation. Our study demonstrates that HS2 in the Il4 locus is a critical GATA-3 binding site that regulates lineage specific IL-4 expression. Deletion of HS2 markedly impaired maintenance of H3K9/K14 acetylation and the onset of H3K4 methylation on the Il4 locus, both of which are required for transcriptional permissibility, leading to the lack of Il4 transcription. GATA-3 overexpression failed to reconstitute these defects. We found that HS2, as a specific target of the GATA-3 mediated epigenetic modification on the Il4 locus, is an indispensable enhancer. Therefore, we found a novel regulation of Th2 cytokine genes by GATA-3 protein. Less