DAPK2 is a novel E2F1/KLF6 target gene involved in their proapoptotic function
DAPK2 is a novel E2F1/KLF6 target gene involved in their proapoptotic function
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DOI：
10.1038/onc.2008.179
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发表时间：
2008-09-01
期刊：
影响因子：
8
通讯作者：
Tschan, M. P.
中科院分区：
文献类型：
--
作者：
Britschgi, A.;Trinh, E.;Tschan, M. P.
死亡相关蛋白激酶2（DAPK 2）属于促凋亡Ca（2+）/钙调素调节的丝氨酸/苏氨酸激酶家族。我们最近发现DAPK 2作为粒细胞分化过程中的增强因子。为了鉴定DAPK 2的转录调节子，我们克隆了DAPK 2基因5 '侧翼区的2.7kb。我们发现E2 F1和Kruppel样因子6（KLF 6）强烈激活DAPK 2启动子。我们将E2 F1和KLF 6反应元件映射到外显子1的富含GC的区域50，该区域含有KLF 6和Sp1的几个结合位点，但不包含E2 F。此外，我们发现E2 F1和KLF 6对DAPK 2的转录激活依赖于Sp1，使用Sp1/KLF 6缺陷的昆虫细胞，光神霉素A处理以阻断Sp1结合或Sp1敲低细胞。染色质免疫沉淀显示，招募的Sp1和较小程度的E2 F1和KLF 6的DAPK 2启动子。骨肉瘤细胞中E2 F1的激活导致细胞死亡导致内源性DAPK 2激酶的增加。DAPK 2表达的抑制导致E2 F1活化后细胞死亡显著减少。类似地，H1299细胞中的KLF 6表达增加了DAPK 2水平，伴随着细胞死亡，DAPK 2敲低后细胞死亡显著降低。此外，E2 F1和KLF 6在激活DAPK 2启动子方面表现出合作。总之，我们的研究结果确定DAPK 2是细胞死亡反应中E2 F1和KLF 6的新型Sp1依赖性靶基因。
Death-associated protein kinase 2 (DAPK2) belongs to a family of proapoptotic Ca(2+)/calmodulin-regulated serine/threonine kinases. We recently identified DAPK2 as an enhancing factor during granulocytic differentiation. To identify transcriptional DAPK2 regulators, we cloned 2.7 kb ofthe 5'-flanking region ofthe DAPK2 gene. We found that E2F1 and Kruppel-like factor 6 (KLF6) strongly activate the DAPK2 promoter. We mapped the E2F1 and KLF6 responsive elements to a GC-rich region 50 of exon 1 containing several binding sites for KLF6 and Sp1 but not for E2F. Moreover, we showed that transcriptional activation of DAPK2 by E2F1 and KLF6 is dependent on Sp1 using Sp1/KLF6-deficient insect cells, mithramycin A treatment to block Sp1-binding or Sp1 knockdown cells. Chromatin immunoprecipitation revealed recruitment of Sp1 and to lesser extent that of E2F1 and KLF6 to the DAPK2 promoter. Activation of E2F1 in osteosarcoma cells led to an increase of endogenous DAPK2 paralleled by cell death. Inhibition of DAPK2 expression resulted in significantly reduced cell death upon E2F1 activation. Similarly, KLF6 expression in H1299 cells increased DAPK2 levels accompanied by cell death that is markedly decreased upon DAPK2 knockdown. Moreover, E2F1 and KLF6 show cooperation in activating the DAPK2 promoter. In summary, our findings establish DAPK2 as a novel Sp1-dependent target gene for E2F1 and KLF6 in cell death response.