Skip to main content
. Author manuscript; available in PMC: 2008 May 1.
Published in final edited form as: Mol Cell. 2008 Mar 28;29(6):755–766. doi: 10.1016/j.molcel.2008.01.020

Figure 1. TBL1 and TBLR1 are required for dismissal of distinct corepressors.

Figure 1

(A) Single-cell nuclear microinjection of purified IgGs against either TBL1 or TBLR1 inhibited transcriptional activation of a T3RE-dependent and of an ERE-dependent LacZ reporter in Rat1 cells. Depletion of TBLR1, but not TBL1, could be rescued by downregulating NCoR and SMRT by specific siRNAs. (B) A LacZ reporter driven by a 1.2kb fragment of the pS2 promoter was used in MCF7 to screen for other corepressors removal by siRNAs. Downregulation of CtBP1and CtBP2 fully rescued estrogen-induced activation in absence of TBL1. (C) αTBL1 IgGs microinjection blocked activation of LacZ reporters driven by an ERE response element, a PPARγ-responsive fragment of the AOX3 promoter, a TR-responsive fragment of the Dio1 promoter and a 3xp65 response element. All were rescued by removal of CtBP1 and CtBP2 by specific siRNAs microinjection. (D) Analysis of GREB1 mRNA expression in transiently transfected MCF7 cells by RT-PCR at 4h after induction. Expression of the GAPDH gene was used for normalization. Validation of the siRNA used here is shown in Supplemental Figure S1.