Transcriptional regulation of human MUC4 gene: identification of a novel inhibitory element and its nuclear binding protein
Transcriptional regulation of human MUC4 gene: identification of a novel inhibitory element and its nuclear binding protein
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人MUC4基因的转录调控：新型抑制元件及其核结合蛋白的鉴定
DOI：
10.1007/s11033-013-2591-6
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发表时间：
2013-08-01
影响因子：
2.8
通讯作者：
Miao, Yi
中科院分区：
文献类型：
--
作者：
Zhang, Jing-Jing;Zhu, Yi;Miao, Yi
人黏液蛋白4 （mucin 4, MUC4）在胰腺腺癌和肿瘤细胞系中异常表达，而在正常胰腺中未检测到，提示其在胰腺癌发生发展中的重要作用。虽然其转录调控已被研究的相当详细，一些重要的因素仍然未知。本研究的目的是证明MUC4启动子中存在一种新的抑制元件，并表征其一些结合蛋白。通过荧光素酶报告基因分析，我们利用一系列缺失和突变报告基因构建了MUC4启动子中- 2530和- 2521核苷酸之间的抑制元件。Bxpc-3细胞核提取物的电泳迁移迁移分析（EMSA）表明，该元件与一种蛋白质或蛋白质复合物结合。结合该元件的蛋白经质谱纯化鉴定为阴阳1 （YY1）。Supershift实验和染色质免疫沉淀（ChIP）实验证实YY1在体外和体内与该元件结合。此外，瞬时过表达YY1显著抑制MUC4启动子活性和内源性MUC4蛋白表达。总之，我们在这里报道了人类MUC4启动子中的一个新的抑制元件。这为MUC4基因调控提供了额外的数据，表明YY1可能是MUC4异常表达的潜在靶点。
The human mucin 4 (MUC4) is aberrantly expressed in pancreatic adenocarcinoma and tumor cell lines, while remaining undetectable in normal pancreas, indicating its important role in pancreatic cancer development. Although its transcriptional regulation has been investigated in considerable detail, some important elements remain unknown. The aim of the present study was to demonstrate the existence of a novel inhibitory element in the MUC4 promoter and characterize some of its binding proteins. By luciferase reporter assay, we located the inhibitory element between nucleotides −2530 and −2521 in the MUC4 promoter using a series of deletion and mutant reporter constructs. Electrophoretic mobility shift assay (EMSA) with Bxpc-3 cell nuclear extracts revealed that one protein or protein complex bind to this element. The proteins binding to this element were purified and identified as Yin Yang 1 (YY1) by mass spectrometry. Supershift assay and chromatin immunoprecipitation (ChIP) assay confirmed that YY1 binds to this element in vitro and in vivo. Moreover, transient YY1 overexpression significantly inhibited MUC4 promoter activity and endogenous MUC4 protein expression. In conclusion, we reported here a novel inhibitory element in the human MUC4 promoter. This provides additional data on MUC4 gene regulation and indicates that YY1 may be a potential target for abnormal MUC4 expression.