Figure 6. JMJD2A upregulates FHL1 transcription synergistically with SRF/myocardin.

(A) A ³²P-labeled oligonucleotide probe containing the CArG box from the FHL1 promoter was incubated with the in vitro–translated (ivt) SRF in the presence or absence of anti-SRF antibody or a 100-fold molar excess of unlabeled, WT, or mutant (mut) oligonucleotides. SRF forms a complex with the WT oligonucleotide probe (SRF-CArG) that can be super-shifted (ss) by an anti-SRF antibody. ns, nonspecific nucleoprotein complex. (B) A 1.9-kb FHL1 promoter–driven luciferase construct was transfected along with the plasmids indicated into QBI293A cells. FHL1-luciferase activities were measured 24 hours after transfection and normalized against cotransfected β-galactosidase. (C) Responsiveness of the deletion and site-specific mutants of the FHL1-luc reporter to myocardin and JMJD2A in QBI293A cells. Deletion or site-specific mutation of the SRF-binding site CArG box impairs the responsiveness of the promoter to myocardin and JMJD2A. (D) Relative activity of the FHL1-luc reporter in SRF-null and WT ES cells in the presence and absence of cotransfected expression plasmids as indicated. Representative of 3 independent experiments is shown. (E) Relative luciferase activity of the ANP-luc reporter and (F) the sm22-luc reporter in QBI293A cells transfected with the plasmids indicated. Myocardin-activated ANP- and sm22-luc reporters that can be further upregulated by WT but not mutant JMJD2A. Data shown are mean ± SEM of 3 independent experiments. *P < 0.05.