Integration of the activation of the human hyaluronan synthase 2 gene promoter by common cofactors of the transcription factors retinoic acid receptor and nuclear factor κB
Integration of the activation of the human hyaluronan synthase 2 gene promoter by common cofactors of the transcription factors retinoic acid receptor and nuclear factor κB
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DOI：
10.1074/jbc.m607871200
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发表时间：
2007-04-13
影响因子：
4.8
通讯作者：
Carlberg, Carsten
中科院分区：
文献类型：
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作者：
Saavalainen, Katri;Tammi, Markku I.;Carlberg, Carsten
透明质酸 (HA) 是脊椎动物细胞外基质的一种多糖，由影响众多生理过程的三种相关 HA 合酶 (HAS) 产生。我们在计算机中筛选了 HAS2 启动子的前 2250 bp 的转录因子反应元件 (RE)，发现 1 个簇，其中包含 2 个视黄酸 (RA) RE、3 个离散的 NF-κ B 因子和 12 个 Sp1 RE。与此同时，我们使用染色质免疫沉淀测定扫描了 HaCaT 人永生化角质形成细胞中的 9 个重叠启动子区域，以识别介导蛋白、共激活蛋白和辅抑制蛋白以及 Sp1 转录因子对全反式 RA 和肿瘤坏死因子-α (TNF-α) 的反应。我们发现全反式 RA 调节 RA 受体和几个共调节子与位置 1230 处包含 RARE 簇的区域的结合。在报告基因测定中，各个启动子区域的全反式 RA 诱导支持了该区域的重要性。同样，我们通过染色质免疫沉淀测定以及核提取物凝胶迁移测定表明，TNF-α 诱导 NF-κ B 与位置 -380、-1420 和 -1890 的区域结合，证明了其与 RNA 聚合酶 II 和辅因子蛋白的关联，并证实了体内各个启动子区域的功能。这些发现部分解释了全反式 RA 和 TNF-α 对 HAS2 mRNA 的诱导，并提供了不同转录因子家族如何使用相同辅因子发挥作用的示例。
Hyaluronan ( HA) is a polysaccharide of the vertebrate extracellular matrix, produced by three related HA synthases ( HASs) that influence numerous physiological processes. We screened the first 2250 bp of the HAS2 promoter for transcription factor response elements ( REs) in silico and found 1 cluster of 2 retinoic acid ( RA) REs, 3 discrete NF-kappa B factors, and 12 Sp1 REs. In parallel, we scanned nine overlapping promoter regions in HaCaT human immortalized keratinocytes using chromatin immunoprecipitation assays to identify binding of mediator, coactivator, and corepressor proteins and Sp1 transcription factor in response to all-trans-RA and tumor necrosis factor-alpha (TNF-alpha). We found that all-trans-RA modulated the binding of the RA receptor and several coregulators to the region containing the RARE cluster at position - 1230. The importance of this region is supported in reporter gene assays by the all-trans-RA induction of the respective promoter region. Similarly, we showed by chromatin immunoprecipitation assays as well as by gel-shift assays with nuclear extracts that TNF-alpha induced NF-kappa B binding to regions at positions -380, -1420, and -1890, demonstrated its association with RNA polymerase II and cofactor proteins, and confirmed the functionality of the respective promoter regions in vivo. These findings partially explain the induction of HAS2 mRNA by all-trans-RA and TNF-alpha and provide an example how the action of different transcription factor families can use the same cofactors.