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

Objective:To investigate the feedback enhancement effect of LRP16 on ERα mediated transcriptional activation.Methods:ERα mode-promotor or LRP16 promotor fragment（-101bp to-14 bp） which confers 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.