Genetic regulation and immunological function of ERAP2 haplotypes

我们建议剖析ERAP2的遗传控制和免疫功能，该基因以前被证明是 在抗原加工中发挥作用。ERAP2基因座上的两种单倍型是由天然的 频率较高的单倍型(单倍型B)与克罗恩病风险相关的人类选择 疾病、强直性脊柱炎、先兆子痫和艾滋病毒易感性。令人费解的是，而单倍型A编码 单倍型B是一种全长的酶，可以裂解病毒的多肽来呈递抗原，它编码一种转录本 被胡说八道的腐烂有效地降解了。为什么自然选择会保持一种看似 该基因的功能丧失版本以及它会通过什么机制导致疾病？我们发现了一个可能的 通过研究250名健康人的单核细胞来源的树突状细胞的抗病毒反应来解释。在……里面 对体外刺激的反应，流感感染诱导了两个未注释的短异构体的转录 来自单倍型B，在静息或干扰素-β刺激的细胞中没有观察到。这一观察结果， 结合以前的免疫学结果和自然选择的证据，我们提出了这样的假设 这两种ERAP2单倍型编码不同的基因产物，在病毒抗原处理中扮演不同的角色 和展示。在这项提案中，我们将应用最先进的分子和免疫学工具来测试这一点 假设。在目标1中，我们将使用功能基因组技术(长阅读RNA-seq、核糖体足迹 和蛋白质组学)来表征ERAP2的转录和翻译特性 一系列病毒挑战。在目标2中，我们将使用报告分析和 CRISPR/Cas9介导的基因组编辑。在目标3中，我们将测量不同的ERAP2亚型如何影响 抗原提呈和T细胞功能。我们的研究结果将为我们揭示该基因的调控和功能提供新的线索。 ERAP2单倍型，并有助于理解自然选择下的遗传变异如何 导致自身免疫性疾病。

We propose to dissect the genetic control and immunological function of ERAP2, a gene previously shown to play a role in antigen processing. Two haplotypes at the ERAP2 locus have been maintained by natural selection in humans where the more frequent haplotype (Haplotype B) is associated with risk for Crohn's disease, ankylosing spondylitis, preeclampsia and HIV susceptibility. Enigmatically, while Haplotype A encodes a full-length enzyme that cleaves viral peptides for antigen presentation, Haplotype B encodes a transcript efficiently degraded by nonsense-mediated decay. Why would natural selection have maintained a seemingly loss-of-function version of the gene and by what mechanism would it cause disease? We found a possible explanation by studying the antiviral response of monocyte-derived dendritic cells in 250 healthy individuals. In response to in vitro stimulations, influenza infection induced the transcription of two unannotated short isoforms from Haplotype B that are not observed in resting or interferon-beta stimulated cells. This observation, combined with previous immunological results and evidence of natural selection, leads us to hypothesize that the two ERAP2 haplotypes encode distinct gene products that play divergent roles in viral antigen processing and presentation. In this proposal, we will apply state-of-the-art molecular and immunological tools to test this hypothesis. In Aim 1, we will use functional genomic techniques (long-read RNA-seq, ribosomal footprinting and proteomics) to characterize the transcriptional and translational properties of ERAP2 in response to a spectrum of viral challenges. In Aim 2, we will map the cis-genetic control of ERAP2 using reporter assays and CRISPR/Cas9-mediated genome editing. In Aim 3, we will measure how different ERAP2 isoforms affect antigen presentation and T cell function. Our findings will shed new light on the regulation and function of the ERAP2 haplotypes and contribute to the understanding of how genetic variants under natural selection could cause autoimmune disease.