Interferon regulatory factors (IRFs) repress transcription of the chicken ovalbumin gene
Interferon regulatory factors (IRFs) repress transcription of the chicken ovalbumin gene
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DOI：
10.1016/j.gene.2009.03.016
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发表时间：
2009-06-15
期刊：
影响因子：
3.5
通讯作者：
Sanders, Michel M.
中科院分区：
文献类型：
--
作者：
Dougherty, Dawne C.;Park, Hyi-Man;Sanders, Michel M.
尽管卵白蛋白（Ov）基因作为研究脊椎动物组织特异性、类固醇激素诱导的基因表达的模型已有几十年，但调控该基因的机制仍然难以捉摸。Ov在非输卵管组织和雌激素缺乏的输卵管中受到位于-130至-100的强阻遏位点的抑制，并指定CAR为COUP-TF邻近阻遏因子。本研究的目的是鉴定CAR结合蛋白。转录因子数据库搜索显示，一个假定的干扰素刺激反应元件（ISRE），结合干扰素调节因子（irf），位于该区域。凝胶迁移转移试验表明，与CAR位点结合的蛋白质被IRF抗体识别，而ISRE中的突变会消除这种结合。为了确定对Ov的组织特异性调控负责的IRF(s)，在接受或不接受雌激素治疗的鸡的7个组织中测量了IRF -4、-8和-10的mRNA水平。PCR实验表明，IRF-8和-10在鸡的所有组织中均有表达，而IRF-4的表达模式则非常有限。用OvCAT（氯霉素乙酰转移酶）报告基因构建的转染实验表明，即使在类固醇激素存在的情况下，IRF-4和IRF-10也能够抑制Ov基因，并且ISRE中的核苷酸是抑制Ov基因所必需的。这些实验表明，与CAR位点相关的抑制活性是由IRF家族成员介导的，并表明IRF成员也抑制非输卵管组织中的Ov。(C) 2009 Elsevier B.V.版权所有
Although the ovalbumin (Ov) gene has served as a model to study tissue-specific, steroid hormone-induced gene expression in vertebrates for decades, the mechanisms responsible for regulating this gene remain elusive. Ov is repressed in non-oviduct tissue and in estrogen-deprived oviduct by a strong repressor site located from -130 to -100 and designated CAR for COUP-TF adjacent repressor. The goal of this study was to identify the CAR binding protein(s). A transcription factor database search revealed that a putative interferon-stimulated response element (ISRE), which binds interferon regulatory factors (IRFs), is located in this region. Gel mobility shift assays demonstrated that the protein(s) binding to the CAR site is recognized by an IRF antibody and that mutations in the ISRE abolish that binding. In hopes of identifying the IRF(s) responsible for the tissue-specific regulation of Ov, mRNA levels for IRFs-4, -8, and -10 were measured in seven tissues from chicks treated with or without estrogen. PCR experiments showed that both IRF-8 and -10 are expressed in all chick tissues tested whereas IRF-4 has a much more limited expression pattern. Transfection experiments with OvCAT (chloramphenicol acetyltransferase) reporter constructs demonstrated that both IRF-4 and IRF-10 are capable of repressing the Ov gene even in the presence of steroid hormones and that nucleotides in the ISRE are required for repression. These experiments indicate that the repressor activity associated with the CAR site is mediated by IRF family members and suggest that IRF members also repress Ov in non-oviduct tissues. (C) 2009 Elsevier B.V. All rights reserved.