Transcriptional regulation of the rat Mrp3 gene promoter by the specificity protein (Sp) family members and CCAAT/enhancer binding proteins
Transcriptional regulation of the rat Mrp3 gene promoter by the specificity protein (Sp) family members and CCAAT/enhancer binding proteins
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DOI：
10.1007/s11373-005-9002-5
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发表时间：
2005-10-01
影响因子：
11
通讯作者：
Huang, JD
中科院分区：
文献类型：
--
作者：
Tzeng, SJ;Chang, WC;Huang, JD
大鼠Mrp 3基因5 '侧翼区的序列被确定为翻译起始位点上游2723 bp。在肝癌细胞中，对Mrp 3启动子活性至关重要的调控区的特征在于-157和-106 bp之间。在这个序列中，我们确定了C/EBP和Sp1的假定结合位点。EMSA和supershift分析证明了Sp1、Sp3、C/EBP α、β和δ的特异性结合。在果蝇SL 2细胞中，Sp1和Sp3都反式激活Mrp 3最小启动子（pWT-157）。结构和功能分析表明，C/EBP，Sp1和Sp3的结合位点是Mrp 3表达细胞（包括：H4 IIE，H4 IIE C3，BRL 3A，克隆9和RAT 2）中大鼠Mrp 3基因转录所必需的。共转染实验表明，C/EBP转录因子通过识别C/EBP（-157/-140）元件并与Sp1（3）和Sp1（4）（-140/-106）顺式作用元件相互作用，调节Mrp 3基因启动子的基础活性和组织特异性活性。本研究发现C/EBP和Sp1/Sp3通过近端（-157/-106）区域协同调控大鼠Mrp 3基因启动子活性。提示Mrp 3基因表达可能存在另一种微调调控机制。
The sequence of the 5'-flanking region of the rat Mrp3 gene was determined up to 2723 bp upstream of the translation start site. Regulatory regions crucial for Mrp3 promoter activity were characterized between -157 and -106 bp in hepatoma cells. Within this sequence we identified putative binding sites for C/EBP and Sp1. EMSA and supershift assays demonstrated specific binding of Sp1, Sp3, C/EBP alpha, beta, and delta. In Drosophila SL2 cells, both Sp1 and Sp3 transactivated the Mrp3 minimal promoter (pWT-157). Structural and functional analysis demonstrated that binding sites for C/EBPs, Sp1 and Sp3 were essential for transcription of the rat Mrp3 gene in Mrp3-expressing cells (including: H4IIE, H4IIE C3, BRL 3A, Clone 9, and RAT 2). Cotransfection assays demonstrated that C/EBP transcription factors modulated the basal and tissue specific activity of the Mrp3 gene promoter by recognition of the C/EBP (-157/-140) element and through functional cooperation with factors interacting with the Sp1 (3) and Sp1 (4) (-140/-106) cis-acting elements. In this study, we found C/EBPs and Sp1/Sp3 cooperatively regulated the promoter activity of rat Mrp3 gene through proximal (-157/-106) region. It suggested another fine-tune regulation mechanism may involve in Mrp3 gene expression.