Yildirim Hatice, Köçkar Feray
Department of Biology, Faculty of Art and Science, Balikesir University, 10145 Balikesir, Turkey.
Cell Biol Int. 2009 Sep;33(9):1002-7. doi: 10.1016/j.cellbi.2009.05.005. Epub 2009 Jun 18.
Carbonic anhydrase IX (CAIX) is a membrane-associated carbonic anhydrase (CA) that is overexpressed in a variety of tumor types and associated with increased metastasis, giving a poor prognosis. Transcriptional regulation of transmembrane protein CAIX is complex. We describe further characterization of the 1.2kb hCA9 promoter, and the effect of TGF-beta on the transcriptional activity and expression of hCAIX in Hep3B cells. Transcriptional activity of different promoter regions of hCA9 promoter showed the presence of negative regulatory region between -300bp and -500bp of hCAIX promoter. The -116/+38 region was enough for basal transcriptional activity in Hep3B cells. TGF-beta upregulates all promoter regions of hCA9 with the highest beig for -466/+38 that has a negatively regulated region. The transcriptional activation of hCA9 promoter by TGF-beta is consistent with hCAIX mRNA levels revealed by RT-PCR and hCAIX protein expression levels by flow cytometry in Hep3B cells.
碳酸酐酶IX（CAIX）是一种与膜相关的碳酸酐酶（CA），在多种肿瘤类型中过度表达，并与转移增加相关，预后较差。跨膜蛋白CAIX的转录调控很复杂。我们描述了1.2kb hCA9启动子的进一步特征，以及转化生长因子-β（TGF-β）对Hep3B细胞中hCAIX转录活性和表达的影响。hCA9启动子不同区域的转录活性表明，hCAIX启动子-300bp至-500bp之间存在负调控区域。-116/+38区域足以支持Hep3B细胞中的基础转录活性。TGF-β上调hCA9的所有启动子区域，其中-466/+38区域上调幅度最大，该区域存在负调控区域。TGF-β对hCA9启动子的转录激活与Hep3B细胞中RT-PCR显示的hCAIX mRNA水平以及流式细胞术检测的hCAIX蛋白表达水平一致。
