Post-transcriptional regulation of ULBP1 ligand for the activating immunoreceptor NKG2D involves 3′ untranslated region
Post-transcriptional regulation of ULBP1 ligand for the activating immunoreceptor NKG2D involves 3′ untranslated region
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DOI：
10.1016/j.humimm.2011.03.005
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发表时间：
2011-06-01
期刊：
影响因子：
2.7
通讯作者：
Kalberer, Christian P.
中科院分区：
文献类型：
--
作者：
Himmelreich, Heike;Mathys, Arina;Kalberer, Christian P.
活化免疫受体NKG 2D的应激诱导ULBP 1细胞表面配体允许自然杀伤（NK）和T细胞识别和裂解肿瘤细胞。对调节ULBP 1表达的机制的理解是有限的，但它对于利用NKG 2D依赖性抗肿瘤反应是重要的。我们在Jurkat和HeLa细胞中研究了3'非翻译区（3' UTR）在ULBP 1表达的转录后调控中的作用。对2.4kb长的3' UTR的分析揭示了四个富含AU的元件（ARE）和超过200个推定的microRNA结合位点的存在。含有ULBP 1 -3' UTR序列的荧光素酶报告基因构建体的稳定或瞬时递送导致荧光素酶活性强烈降低至全长3' UTR的7-22%或其片段的19%-62%，表明3' UTR对ULBP 1基因的调控的贡献。引入ARE基序的突变显著降低了荧光素酶活性，表明ARE的mRNA稳定作用。在ULBP 1特异性的候选microRNA中，我们发现miR-140- 5 p/-409-3p/-433-3p/-650在HeLa和Jurkat细胞中表达，并且microRNA参与通过带有种子序列突变的构建体的荧光素酶报告基因测定得到支持。然而，microRNA过表达或microRNA加工酶Drosha的部分沉默并没有明确阐明microRNA在ULBP 1调控中的作用。总之，这些结果为ULBP 1在转录后水平的新的3'UTR介导的调节机制提供了证据。(C)2011年美国组织相容性和免疫遗传学学会。爱思唯尔公司出版。All rights reserved.
The stress-inducible ULBP1 cell surface ligand for the activating immunoreceptor NKG2D allows recognition and lysis of tumor cells by natural killer (NK) and T cells. Understanding of mechanisms regulating ULBP1 expression is limited, but it is important for exploiting NKG2D-dependent antitumor responses. We studied the role of 3' untranslated region (3' UTR) in post-transcriptional regulation of ULBP1 expression in Jurkat and HeLa cells. Analysis of 2.4 kb-long 3' UTR revealed the presence of four AU-rich elements (ARE) and more then 200 putative microRNA binding sites. Stable or transient delivery of luciferase reporter constructs containing ULBP1-3' UTR sequences resulted in a strong reduction of luciferase activity to 7-22% with the full-length 3' UTR or 19%-62% with its fragments, indicating a contribution of 3' UTR to regulation of ULBP1 gene. Mutations introduced to ARE motifs significantly diminished luciferase activity, suggesting mRNA stabilizing effect of ARE. Among ULBP1-specific candidate microRNAs, we found miR-140-5p/-409-3p/-433-3p/-650 expressed in HeLa and Jurkat cells, and the microRNA involvement was supported by luciferase reporter assays with constructs carrying seed sequence mutations. However, microRNA overexpression or partial silencing of the microRNA processing enzyme Drosha did not equivocally clarify the role of microRNAs in regulation of ULBP1. Altogether these results provide evidence for a novel 3' UTR-mediated mechanism of regulation of ULBP1 at the post-transcriptional level. (C) 2011 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.