Suppression of Krüppel-like factor 5 basal expression by CREB1 binding to far distal element.

Q3 Biochemistry, Genetics and Molecular Biology Tumor Biology Pub Date : 2023-01-01 DOI:10.3233/TUB-230017

Nozomi Mihara, Kazushi Imai

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Abstract

Background: Krüppel-like factor 5 (KLF5) is a transcription factor regulating the proliferation and differentiation of epithelial cells, and its uncontrolled expression is closely associated with carcinoma progression. Sp3 binding to the minimal essential region (MER) of KLF5 gene is critical for KLF5 basal expression, but the expression control mechanism is unknown.

Objective: This study aimed to identify a regulatory region for KLF5 basal expression and the binding protein in carcinoma cells by analyzing the promoter upstream region.

Methods: Reporter assays determined the silencer region. The protein binding to the region was identified by database analysis and ChIP assay. The protein mediating the interaction between the region and the MER was confirmed through chromosome conformation capture (3 C) on ChIP assay. The effects of the protein on KLF5 expression were analyzed using qRT-PCR and western blot.

Results: Reporter assay localized the 425-region from upstream KLF5 gene as the silencer. Database analysis and ChIP assay found CREB1 binding to the 425-region. CREB1 siRNA or mutation of CREB1-binding site in the 425-region increased luciferase activities and decreased the binding to 425-region. 3 C on ChIP assay showed that CREB1 mediated interaction of the 425-region and the MER. CREB1 overexpression decreased endogenous KLF5 expression and luciferase activity.

Conclusions: The 425-region is the silencer of KLF5 basal expression, and CREB1 binding suppresses the expression.

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CREB1结合远端元件抑制kr ppel样因子5基础表达。

背景:kr ppel样因子5 (KLF5)是调节上皮细胞增殖和分化的转录因子，其不受控制的表达与肿瘤进展密切相关。Sp3结合到KLF5基因的最小必需区(minimum essential region, MER)对KLF5的基础表达至关重要，但其表达调控机制尚不清楚。目的:本研究旨在通过分析KLF5上游启动子区，寻找癌细胞中KLF5基础表达及其结合蛋白的调控区域。方法:采用报告法测定消音区。通过数据库分析和ChIP实验鉴定了与该区域结合的蛋白。通过芯片上的染色体构象捕获(3c)证实了介导该区域与MER相互作用的蛋白质。采用qRT-PCR和western blot分析该蛋白对KLF5表达的影响。结果:报告者实验定位了上游KLF5基因425区为消声器。数据库分析和ChIP检测发现CREB1与425区结合。CREB1 siRNA或425区CREB1结合位点突变增加荧光素酶活性，降低与425区的结合。ChIP上的3c实验显示CREB1介导425区与MER的相互作用。CREB1过表达降低内源性KLF5表达和荧光素酶活性。结论:425区是KLF5基础表达的沉默者，CREB1结合抑制KLF5基础表达。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Tumor Biology 医学-肿瘤学

CiteScore

5.40

自引率

0.00%

发文量

审稿时长

1 months

期刊介绍： Tumor Biology is a peer reviewed, international journal providing an open access forum for experimental and clinical cancer research. Tumor Biology covers all aspects of tumor markers, molecular biomarkers, tumor targeting, and mechanisms of tumor development and progression. Specific topics of interest include, but are not limited to: Pathway analyses, Non-coding RNAs, Circulating tumor cells, Liquid biopsies, Exosomes, Epigenetics, Cancer stem cells, Tumor immunology and immunotherapy, Tumor microenvironment, Targeted therapies, Therapy resistance Cancer genetics, Cancer risk screening. Studies in other areas of basic, clinical and translational cancer research are also considered in order to promote connections and discoveries across different disciplines. The journal publishes original articles, reviews, commentaries and guidelines on tumor marker use. All submissions are subject to rigorous peer review and are selected on the basis of whether the research is sound and deserves publication. Tumor Biology is the Official Journal of the International Society of Oncology and BioMarkers (ISOBM).