LRP16反馈增强ERα介导转录激活活性的研究

Study of feedback enhancement effect of LRP16 on ERα-mediated transcriptional activation

目的:探讨LRP16对雌激素受体α(ERα)介导转录激活活性的反馈增强作用。方法:ERα模式启动子调控的荧光素酶报告子(3×ERE-Luc)或GC富含的ER反应性LRP16启动子S10(-101bp到-14 bp)调控的荧光素酶报告子(pGL-3-S10)与雌激素受体α(ERα)真核表达载体、LRP16真核表达载体(pcDNA3.1-16)共转染MCF-7细胞,测定3×ERE-Luc和pGL-3-S10的相对荧光素酶活性;3×ERE-Luc或pGL-3-S10与ERα真核表达载体、针对LRP16的小干扰RNA(LRP16-siRNA374、LRP16-siRNA668)或对照小干扰RNA(control-siRNA)共转染MCF-7细胞,测定3×ERE-Luc和pGL-3-S10的相对荧光素酶活性。结果:LRP16增强3×ERE-Luc和pGL-3-S10的相对荧光素活性,抑制LRP16表达显著削弱了3×ERE-Luc和pGL-3-S10的相对荧光素活性,并呈现剂量依赖性,该效应依赖于雌激素对ERα的激活。结论:ERα调控的靶基因LRP16反馈增强ERα介导的转录激活活性,是ERα的一个共激活因子。

Objectlve：To investigate the feedback enhancement effect of LRP16 on ERα mediated transcriptional activation. Methods：ERa mode-promotor or LRP16 promotor fragment （-101bp to -14 bp） which coffers the maximmal ER responsiveness controlled luciferase expression vector（3 ×ERE-Luc or pGL-3-S10）was co-transferred with ERα and pcDNA3.1-16 into MCF-7 cell;3 × ERE-Luc or pGL-3-S10 was co-transferred with ERα and either LRP16 specific siRNA（ LRP16-siRNA374, LRP16-siRNA668） or control-siRNA into MCF-7 cell, then the relative luciferase activity of 3 × ERE-Luc or pGL-3-S10 was measured with dual-luciferase report assay 1000 systems. Result：The reporter activitives of 3 ERE-Luc and pGL-3-S10 were enhanced by LRP16 in a dose-dependent manner. This effect was abolished when estrogen was deprived. Inhibition of LRP16 expression attenuated the reporter activities. Conclusion：ERα-mediated transcriptional activation is feedbackly enhanced by it＇s target gene LRP16, and LRP16 is a co-activator of ERα .