Physical interaction of the activator protein-1 factors c-Fos and c-Jun with Cbfa1 for collagenase-3 promoter activation
Physical interaction of the activator protein-1 factors c-Fos and c-Jun with Cbfa1 for collagenase-3 promoter activation
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DOI：
10.1074/jbc.m107082200
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发表时间：
2002-01-04
影响因子：
4.8
通讯作者：
Partridge, NC
中科院分区：
文献类型：
--
作者：
D'Alonzo, RC;Selvamurugan, N;Partridge, NC
在此之前，我们发现激活蛋白-1 （AP-1）结合位点和矮子结构域（RD）结合位点及其结合蛋白c-Fos-c-Jun和Cbfa在甲状旁腺激素处理和分化成骨细胞中调节胶原酶-3启动子。在体外实验中，我们发现Cbfa1和c-Fos-c-Jun似乎可以协同结合RD-和ap -1结合位点并形成三元结构。体外和体内共免疫沉淀和酵母双杂交研究进一步证明了Cbfa1与c-Fos和c-Jun在不磷酸化和不与DNA结合的情况下相互作用。此外，只需要Cbfa1的runt结构域就可以与c-Jun和c-Fos相互作用。在哺乳动物细胞中，Cbfa1的过表达增强了c-Jun对ap -1结合位点启动子活性的激活，显示出功能性相互作用。最后，插入打乱AP-1和rd结合位点之间螺旋相位的碱基对也抑制了胶原酶-3启动子的激活。因此，我们提供了直接证据，证明Cbfa1和c-Fos-c-Jun在胶原酶-3启动子中物理相互作用并协同结合AP-1和rd -结合位点。此外，AP-1和rd结合位点似乎以特定所需的螺旋排列组织，促进转录因子相互作用并使启动子激活。
Previously, we determined that the activator protein-1 (AP-1)-binding site and the runt domain (RD)binding site and their binding proteins, c-Fos-c-Jun and Cbfa, regulate the collagenase-3 promoter in parathyroid hormone-treated and differentiating osteoblasts. Here we show that Cbfa1 and c-Fos-c-Jun appear to cooperatively bind the RD- and AP-1-binding sites and form ternary structures in vitro. Both in vitro and in vivo co-immunoprecipitation and yeast two-hybrid studies further demonstrate interaction between Cbfa1 with c-Fos and c-Jun in the absence of phosphorylation and without binding to DNA. Additionally, only the runt domain of Cbfa1 was required for interaction with c-Jun and c-Fos. In mammalian cells, overexpression of Cbfa1 enhanced c-Jun activation of AP-1-binding site promoter activity, demonstrating functional interaction. Finally, insertion of base pairs that disrupted the helical phasing between the AP-1- and RD-binding sites also inhibited collagenase-3 promoter activation. Thus, we provide direct evidence that Cbfa1 and c-Fos-c-Jun physically interact and cooperatively bind the AP-1- and RD-binding sites in the collagenase-3 promoter. Moreover, the AP-1- and RD-binding sites appear to be organized in a specific required helical arrangement that facilitates transcription factor interaction and enables promoter activation.