Friend of GATA 2 physically interacts with chicken ovalbumin upstream promoter-TF2 (COUP-TF2) and COUP-TF3 and represses COUP-TF2-dependent activation of the atrial natriuretic factor promoter.
Friend of GATA (FOG)-2 is a multi-zinc finger transcriptional corepressor protein that binds specifically to GATA4. Gene targeting studies have demonstrated that FOG-2 is required for normal cardiac morphogenesis, including the development of the coronary vasculature, left ventricular compact zone, and heart valves. To better understand the molecular mechanisms by which FOG-2 regulates these cardiac developmental programs, we screened a mouse day 11 embryo library using a yeast two-hybrid interaction trap with the fifth and sixth zinc fingers of FOG-2 as bait. Using this approach, we isolated clones encoding the orphan nuclear receptors chicken ovalbumin upstream promoter-transcription factor (COUP-TF) 2 and COUP-TF3. COUP-TF2-null embryos die during embryonic development with defective angiogenesis and cardiac defects, a pattern that partly resembles the FOG-2-null phenotype. The interaction between COUP-TF2 and FOG-2 in mammalian cells was confirmed by co-immunoprecipitation of these proteins from transfected COS-7 cells. The sites of binding interaction between COUP-TF2 and FOG-2 were mapped to zinc fingers 5 and 6 and fingers 7 and 8 of FOG-2 and to the carboxyl terminus of the COUP-TF proteins. Binding to COUP-TF2 was specific because FOG-2 did not interact with the ligand-binding domains of retinoid X receptor alpha, glucocorticoid receptor, and peroxisome proliferating antigen receptor gamma, which are related to the COUP-TF proteins. Full-length FOG-2 markedly enhanced transcriptional repression by GAL4-COUP-TF2(117-414), but not by a COUP-TF2 repression domain mutant. Moreover, FOG-2 repressed COUP-TF2dependent synergistic activation of the atrial natriuretic factor promoter by both GATA4 and the FOG-2-independent mutant GATA4-E215K. Taken together, these findings suggest that FOG-2 functions as a corepressor for both GATA and COUP-TF proteins.
Huggins
G S
GS
Cardiovascular Biology Laboratory, Harvard School of Public Health, Cardiac Unit, Massachusetts General Hospital, USA. huggins@cvlab.harvard.edu
Bacani
C J
CJ
Boltax
J
J
Aikawa
R
R
Leiden
J M
JM
D016475:3T3 Cells; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics*; D019556:COS Cells; D051838:COUP Transcription Factor I; D051836:COUP Transcription Factors; D002460:Cell Line; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D050991:GATA4 Transcription Factor; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D008024:Ligands; D051379:Mice; D009154:Mutation; D010641:Phenotype; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry; D011965:Receptors, Glucocorticoid / Q000737:chemistry; D018168:Receptors, Retinoic Acid / Q000737:chemistry; D011987:Receptors, Steroid; D011994:Recombinant Proteins / Q000378:metabolism; D047488:Retinoid X Receptors; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D020798:Two-Hybrid System Techniques; D016335:Zinc Fingers
D051838:COUP Transcription Factor I; D051836:COUP Transcription Factors; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; D008024:Ligands; C497590:Nr2f1 protein, mouse; D018160:Receptors, Cytoplasmic and Nuclear; D011965:Receptors, Glucocorticoid; D018168:Receptors, Retinoic Acid; D011987:Receptors, Steroid; D011994:Recombinant Proteins; D047488:Retinoid X Receptors; D014157:Transcription Factors; C492170:Zfpm2 protein, mouse; D009320:Atrial Natriuretic Factor; D005982:Glutathione Transferase