Identification and functional characterization of a novel binding site on TNF-α promoter
Identification and functional characterization of a novel binding site on TNF-α promoter
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DOI：
10.1073/pnas.0630562100
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发表时间：
2003-04-01
影响因子：
11.1
通讯作者：
Amar, S
中科院分区：
文献类型：
--
作者：
Tang, XR;Fenton, MJ;Amar, S
在单核细胞/巨噬细胞谱系中，脂多糖可以快速而短暂地诱导肿瘤坏死因子（TNF）基因的转录。先前的研究表明，在小鼠中，多个NF-kappaB/ rel -结合位点有助于TNF对LIPS的转录反应。但这些调控元件在人类单核细胞中tnf - α基因转录激活中的作用尚不清楚。先前，一种被称为脂多糖诱导的tnf - α因子（LITAF）的转录因子被发现可以调节tnf - α基因的表达。然而，人类(h)LITAF与htnf - α启动子相互作用的特定蛋白质结构域(s)尚未确定。在这项研究中，我们在结合hLITAF的tnf - α启动子中通过足迹识别了一个序列基序CTCCC（-515至-511）。我们还发现hLITAF（165-180氨基酸）区域被命名为肽B，并特异性地介导与htnf - α启动子的结合。当这种肽B刺激THP-1细胞时，足以诱导tnf - α分泌。LPS或肽B诱导tnf - α转录依赖于-515至-511启动子区域的存在，这是hLITAF结合所必需的。总之，这些发现有助于阐明hLITAF/ htnf - α相互作用的机制，以及hLITAF促进htnf - α调节的方式，从而尝试设计新的药物干预措施来治疗tnf相关疾病。
Transcription of the tumor necrosis factor (TNF) gene is rapidly and transiently induced by lipopolysaccharide in cells of monocyte/macrophage lineage. Previous studies have suggested that in the mouse, multiple NF-kappaB/Rel-binding sites contribute to the TNF transcriptional response to LIPS. But the role of these regulatory elements in transcriptional activation of the TNF-alpha gene in human monocytes remains unclear. Previously, a transcription factor, termed lipopolysaccharide-induced TNF-alpha factor (LITAF), was found to regulate TNF-alpha gene expression. However, the specific protein domain(s) of human (h)LITAF that interact with the hTNF-alpha promoter had not been identified. In this study, we identify by footprinting a sequence motif, CTCCC (-515 to -511), within the TNF-alpha promoter that binds to hLITAF. We also identify the region of hLITAF (amino acids 165-180) that was named peptide B and specifically mediates binding to the hTNF-alpha promoter. When THP-1 cells were stimulated with this peptide B, it was sufficient to induce TNF-alpha secretion. Induction of TNF-alpha transcription by LPS or peptide B depended on the presence of the -515 to -511 promoter region, which was found to be essential for hLITAF binding. Together, these findings help to clarify the mechanism of hLITAF/hTNF-alpha interaction and the manner by which hLITAF contributes to hTNF-alpha regulation in an attempt to design new pharmacological interventions to address TNF-related diseases.