Translational control of FOG-2 expression in cardiomyocytes by microRNA-130a.
MicroRNAs are increasingly being recognized as regulators of embryonic development; however, relatively few microRNAs have been identified to regulate cardiac development. FOG-2 (also known as zfpm2) is a transcriptional co-factor that we have previously shown is critical for cardiac development. In this report, we demonstrate that FOG-2 expression is controlled at the translational level by microRNA-130a. We identified a conserved region in the FOG-2 3' untranslated region predicted to be a target for miR-130a. To test the functional significance of this site, we generated an expression construct containing the luciferase coding region fused with the 3' untranslated region of FOG-2 or a mutant version lacking this microRNA binding site. When these constructs were transfected into NIH 3T3 fibroblasts (which are known to express miR-130a), we observed a 3.3-fold increase in translational efficiency when the microRNA target site was disrupted. Moreover, knockdown of miR-130a in fibroblasts resulted in a 3.6-fold increase in translational efficiency. We also demonstrate that cardiomyocytes express miR-130a and can attenuate translation of mRNAs with a FOG-2 3' untranslated region. Finally, we generated transgenic mice with cardiomyocyte over-expression of miR-130a. In the hearts of these mice, FOG-2 protein levels were reduced by as much as 80%. Histological analysis of transgenic embryos revealed ventricular wall hypoplasia and ventricular septal defects, similar to that seen in FOG-2 deficient hearts. These results demonstrate the importance of miR-130a for the regulation of FOG-2 protein expression and suggest that miR-130a may also play a role in the regulation of cardiac development.
Kim
Gene H
GH
Department of Medicine, The University of Chicago, Chicago, IL, USA.
Samant
Sadhana A
SA
Earley
Judy U
JU
Svensson
Eric C
EC
D020413:3' Untranslated Regions; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000502:physiology*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D041681:NIH 3T3 Cells; D014176:Protein Biosynthesis; D014157:Transcription Factors / Q000235:genetics*
D020413:3' Untranslated Regions; D004268:DNA-Binding Proteins; D035683:MicroRNAs; D014157:Transcription Factors; C492170:Zfpm2 protein, mouse