Cloning and characterization of human Golgi phosphoprotein 2 gene (GOLPH2/GP73/GOLM1) promoter

Human Golgi phosphoprotein 2 gene (also known as GOLPH2, GP73 or GOLM1) encodes an epithelial-specific Golgi membrane protein which can be induced by virus infection. It is also overexpressed in a number of tumors and is currently considered as an early diagnosis marker for hepatocellular carcinoma. However, little is known about how GOLPH2 is dysregulated in these disease conditions and the functional implications of its overexpression. The aim of this study is to investigate human GOLPH2 regulation mechanisms. We cloned a 2599 bp promoter fragment of GOLPH2 and found it maintained epithelial specificity. By deletion analysis, a repressive region (-864 to -734 bp), a positive regulatory region (-734 to -421 bp) and a core promoter region (-421 to -79 bp) were identified. Sequence analysis revealed that GOLPH2 core promoter was devoid of canonical TATA element and classified as a TATA-less promoter. Adenoviral early region 1A (E1A) was able to activate GOLPH2 and the CtBP interaction domain of E1A was sufficient but not required for activation. A GC-box motif (-89 to -83 bp) in GOLPH2 core promoter region partly mediated E1A transactivation. These results delineated regulatory regions and functional element in GOLPH2 promoter, elucidated adenoviral E1A stimulation mechanisms and provided insight into GOLPH2 functions.     

PC-1增强受体酪氨酸激酶家族成员EphA3在前列腺癌细胞中的转录

为了研究前列腺癌相关基因(prostate and colon gene 1, PC-1）对受体酪氨酸激酶家族分子EphA3表达的影响,用RT-PCR、实时PCR和Western印迹检测表达不同水平PC-1的前列腺癌细胞系LNCaP和C4-2中EphA3的表达情况. 发现PC-1可诱导EphA3基因表达上调. 采用荧光素酶实验检测PC-1对于EphA3启动子转录活性的影响,结果显示,PC-1对转录起始位点上游916 bp的启动子活性没有影响,而可增强转录起始位点上游2011 bp启动子的活性.对EphA3启动子－916 bp～－2　011 bp区域进行生物信息学分析,结果显示,此区域包含HSF、NF-1、Nkx-2、SP1和GATA-1等多种转录因子结合位点.实验结果表明,PC-1可通过影响EphA3启动子诱导EphA3基因高表达,其调控区域位于转录起始位点上游－2　011　bp至－916 bp之间,提示PC-1可能通过影响一些结合于此区域的转录因子来影响EphA3启动子的转录活性.