Involvement of PU.1 in Mast Cell/Basophil-Specific Function of the Human IL1RL1/ST2 Promoter
Involvement of PU.1 in Mast Cell/Basophil-Specific Function of the Human IL1RL1/ST2 Promoter
复制标题
DOI：
10.2332/allergolint.12-oa-0424
复制
发表时间：
2012-09-01
影响因子：
6.8
通讯作者：
Nishiyama, Chiharu
中科院分区：
文献类型：
--
作者：
Baba, Yosuke;Maeda, Keiko;Nishiyama, Chiharu
背景：人类 IL1RL1/ST2 基因编码 IL33 受体。最近，IL33已被认为是Th2反应发展的关键分子。尽管肥大细胞和嗜碱性粒细胞是IL33的主要靶标，并在IL33介导的Th2型免疫应答中发挥重要作用，但ST2在肥大细胞和嗜碱性粒细胞中的表达机制很大程度上未知。在本研究中，我们分析了人类肥大细胞系LAD2和嗜碱性细胞系KU812中人类ST2启动子的调控机制。方法：用携带从人类基因组DNA及其突变体获得的野生型ST2启动子的质粒，通过报告基因测定测定启动子活性。通过电泳迁移率变动测定（EMSA）鉴定与所识别的顺式元件结合的转录因子。通过分析导入 siRNA 的细胞中的 ST2 mRNA 水平，证实了候选转录因子对 ST2 表达的影响。结果：报告基因分析表明，典型 Ets 家族结合序列的顺式元件对于 LAD2 和 KU812 中的启动子活性至关重要。 Ets 家族转录因子 PU.1 在 EMSA 中与该元件结合。当 siRNA 抑制 PU.1 表达时，KU812 中 ST2 mRNA 水平显着降低。结论：这些观察结果表明，PU.1 作为转录因子正向调节 ST2 启动子，通过肥大细胞和嗜碱性粒细胞中的 Ets 家族相关顺式元件直接反式激活 ST2 启动子。
Background: The human IL1RL1/ST2 gene encodes IL33 receptor. Recently, IL33 has been recognized as a key molecule for the development of Th2 response. Although mast cells and basophils are major targets of IL33 and play important roles in IL33-mediated Th2-type immune responses, the expression mechanism of ST2 in mast cells and basophils is largely unknown. In the present study, we analyzed regulation mechanism of the human ST2 promoter in the human mast cell line LAD2 and basophilic cell line KU812.Methods: Promoter activity was determined by reporter assay with plasmids carrying the wild-type ST2 promoter obtained from human genomic DNA and its mutant. The transcription factor binding to the identified cis-element was identified by an electrophoretic mobility shift assay (EMSA). The effect of candidate transcription factor on ST2 expression was confirmed by analyzing ST2 mRNA level in siRNA-introduced cells.Results: Reporter assay demonstrated that a cis-element of typical Ets-family binding sequence was critical for promoter activity in LAD2 and KU812. An Ets-family transcription factor PU.1 bound to this element in an EMSA. When PU.1 expression was suppressed by siRNA, ST2 mRNA level was significantly reduced in KU812.Conclusions: These observations indicated that PU.1 positively regulates the ST2 promoter as a transcription factor that directly transactivates the ST2 promoter via Ets-family-related cis-element in mast cells and basophils.