Ciais Delphine, Cherradi Nadia, Bailly Sabine, Grenier Emilie, Berra Edurne, Pouyssegur Jacques, Lamarre Jonathan, Feige Jean-Jacques
INSERM EMI 01-05, Department of Cellular Responses and Dynamics, Commissariat à l'Energie Atomique, 17 Rue des Martyrs, F-38054 Grenoble Cedex 9, France.
Oncogene. 2004 Nov 11;23(53):8673-80. doi: 10.1038/sj.onc.1207939.
Vascular endothelial growth factor (VEGF) is an angiogenic cytokine, which plays a major role in tumor angiogenesis. VEGF mRNA expression is controlled by hypoxia, growth factors and hormones through both transcriptional and post-transcriptional mechanisms. VEGF mRNA has a short half-life and its abundance is regulated by the binding of stabilizing (HuR, hRNP-L) and still uncharacterised destabilizing proteins to its 3'-untranslated region. Here, we report that the ACTH-regulated zinc-finger protein TIS11b and its homologs TIS11 and TIS11d interact with the 3'-untranslated region of VEGF mRNA and decrease its stability (half-life reduced from 130 to 60 min). Within the 2201 bp 3'-untranslated region of VEGF mRNA, we identified a 75 bp domain, containing two consensus AU-rich motifs, which binds TIS11b and mediates its destabilizing activity. Ribonucleoprotein (RNP) complex immunoprecipitation experiments allowed us to demonstrate that the interaction between TIS11b and VEGF 3'-untranslated region occurs in live cells. Knocking down TIS11b expression in primary adrenocortical cells with small interfering (si)RNAs clearly indicated that TIS11b participates in the control of both basal and, to a larger extent, ACTH-induced VEGF mRNA expression levels. TIS11b is the first VEGF mRNA-destabilizing protein identified so far and therefore appears as a new potential target in antiangiogenic therapies.
血管内皮生长因子（VEGF）是一种血管生成细胞因子，在肿瘤血管生成中起主要作用。VEGF mRNA的表达通过转录和转录后机制受缺氧、生长因子和激素的控制。VEGF mRNA半衰期短，其丰度通过稳定蛋白（HuR、hRNP-L）和尚未明确的不稳定蛋白与其3'-非翻译区的结合来调节。在此，我们报告促肾上腺皮质激素调节的锌指蛋白TIS11b及其同系物TIS11和TIS11d与VEGF mRNA的3'-非翻译区相互作用并降低其稳定性（半衰期从130分钟降至60分钟）。在VEGF mRNA的2201 bp 3'-非翻译区内，我们鉴定出一个75 bp的结构域，其中包含两个共有富含AU基序，该结构域结合TIS11b并介导其去稳定活性。核糖核蛋白（RNP）复合物免疫沉淀实验使我们能够证明TIS11b与VEGF 3'-非翻译区之间的相互作用发生在活细胞中。用小干扰（si）RNA敲低原代肾上腺皮质细胞中TIS11b的表达清楚地表明，TIS11b参与基础VEGF mRNA表达水平的控制，并且在更大程度上参与促肾上腺皮质激素诱导的VEGF mRNA表达水平的控制。TIS11b是迄今为止鉴定出的首个VEGF mRNA去稳定蛋白，因此似乎是抗血管生成治疗中的一个新的潜在靶点。
