Institute of Biomedical Science & Technology, Konkuk University Hospital, Seoul 143-729, South Korea.
Gene. 2010 Jan 15;450(1-2):121-7. doi: 10.1016/j.gene.2009.11.004.
Klotho is an antiaging gene involved in the suppression of several age-related phenotypes, but few studies have examined the mechanism underlying the regulation of human Klotho gene expression. In this study, we investigated the transcriptional regulation of the Klotho gene by epidermal growth factor (EGF) in HEK293 human embryonic kidney cells. By using serial deletion constructs of the promoter, we identified a proximal 45 bp (-90 to -45) region responsible for EGF-induced promoter activity. The Egr-1-binding motif is located within this region. Forced expression of Egr-1 stimulated Klotho gene promoter activity. A point mutation in the Egr-1-binding motif abrogated promoter inducibility by EGF or ectopic Egr-1 expression. Knockdown of Egr-1 by expression of small interfering RNA (siRNA) attenuated EGF-induced Klotho promoter activity. Further analysis showed that the Ras/MEK/Erk signaling cascade is involved in EGF-induced activation of the Klotho promoter. We conclude that the Klotho gene is activated by EGF in HEK293 cells.
Klotho 是一种抗衰老基因，参与抑制多种与年龄相关的表型，但很少有研究探讨人类 Klotho 基因表达调控的机制。在这项研究中，我们研究了表皮生长因子（EGF）在人胚肾 293 细胞（HEK293）中对 Klotho 基因的转录调控。通过使用启动子的串联缺失构建体，我们确定了负责 EGF 诱导启动子活性的近端 45 个碱基（-90 至-45）区域。Egr-1 结合基序位于该区域内。强制表达 Egr-1 可刺激 Klotho 基因启动子活性。Egr-1 结合基序中的点突变可消除 EGF 或异位 Egr-1 表达对启动子的诱导作用。通过表达小干扰 RNA（siRNA）敲低 Egr-1 可减弱 EGF 诱导的 Klotho 启动子活性。进一步的分析表明，Ras/MEK/Erk 信号级联参与了 EGF 诱导的 Klotho 启动子激活。我们的结论是，EGF 可在 HEK293 细胞中激活 Klotho 基因。
