Itoh Aki, Wang Zhili, Ito Yasuhiro, Reddy Usha R, Itoh Takayuki
Division of Neurology Research, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Biochem Biophys Res Commun. 2004 Jan 16;313(3):612-8. doi: 10.1016/j.bbrc.2003.11.152.
ZPK (zipper protein kinase)/MUK/DLK/MAP3K12, a member of mixed-lineage kinases (MLKs), is expressed in a tissue-specific manner, particularly in developing brain, and likely to contribute to cytodifferentiation, apoptotic elimination, and migration. To understand the preferential expression of ZPK in neuronal tissues, we have analyzed the putative core promoter region upstream of the first exon of the human ZPK gene. The core promoter region is TATA-less, but contains several potential transcription factor-binding motifs such as a GC-box, all of which are well conserved between human and mouse. Reporter assays and 'gel-shift' analysis using SH-SY5Y cells revealed that a xenobiotic responsive element (XRE)-like motif (GGGCGTGTCC) was preferentially recognized by Sp3, and enhanced the core promoter activity. However, the core promoter activity was still potent even in HeLa cells which barely express ZPK. Our results suggest that, for the selective expression of ZPK gene, cell-specific negative regulatory element(s) which locate outside of the core promoter region repress the potent basic promoter activity.
ZPK（拉链蛋白激酶）/MUK/DLK/MAP3K12是混合谱系激酶（MLK）家族的一员，以组织特异性方式表达，尤其在发育中的大脑中表达，可能参与细胞分化、凋亡清除和迁移过程。为了解ZPK在神经组织中的优先表达情况，我们分析了人类ZPK基因第一个外显子上游的假定核心启动子区域。该核心启动子区域不含TATA盒，但包含几个潜在的转录因子结合基序，如GC盒，这些在人和小鼠之间都高度保守。使用SH-SY5Y细胞进行的报告基因检测和“凝胶迁移”分析表明，一个类外源性物质反应元件（XRE）基序（GGGCGTGTCC）被Sp3优先识别，并增强了核心启动子活性。然而，即使在几乎不表达ZPK的HeLa细胞中，核心启动子活性仍然很强。我们的结果表明，对于ZPK基因的选择性表达，位于核心启动子区域之外的细胞特异性负调控元件会抑制强大的基本启动子活性。
