TY - JOUR
T1 - An intact DNA-binding domain is not required for peroxisome proliferator-activated receptor γ (PPARγ) binding and activation on some PPAR response elements
AU - Temple, Karla A.
AU - Cohen, Ronald N.
AU - Wondisford, Sarah R.
AU - Yu, Christine
AU - Deplewski, Dianne
AU - Wondisford, Fredric E.
PY - 2005/2/4
Y1 - 2005/2/4
N2 - Peroxisome proliferator-activated receptor γ (PPARγ) interacts with retinoid X receptor (RXR) on PPAR response elements (PPREs) to regulate transcription of PPAR-responsive genes. To investigate the binding of PPARγ and RXR to PPREs, three mutations were constructed in the DNA-binding domains of PPARγ; two of the mutants maintained the structure of zinc finger I (PPARγ-GS and PPARγ-AA), and a third mutation disrupted the protein structure of zinc finger I (PPARγ-CS). Results indicated that the mutations of PPARγ that maintained intact zinc fingers were capable of binding to a variety of PPREs in the presence of RXR and could activate transcription on several PPREs. In parallel, a mutation was created in the DNA-binding domain of RXRα that maintained the structure of the zinc fingers (RXR-GS) but did not bind DNA and was transcriptionally inactive. Examination of the 3′ half-site of several PPREs revealed that variations from the consensus sequence reduced or abolished transcriptional activity, but conversion to consensus improved transcriptional activity with PPARγ-GS and PPARγ-AA. Examination of the 5′ half-site indicated that the upstream three nucleotides were more important for transcriptional activity than the downstream three nucleotides. Our data demonstrated that stringent binding of RXR to the 3′ half-site of a PPRE is more influential on the binding of the PPARγ/RXR heterodimer than the ability of PPARy to bind DNA. Thus, unlike RXR, PPARγ exhibits promiscuity in binding on a PPRE, suggesting that the definition of a PPRE for PPARγ may need to be expanded.
AB - Peroxisome proliferator-activated receptor γ (PPARγ) interacts with retinoid X receptor (RXR) on PPAR response elements (PPREs) to regulate transcription of PPAR-responsive genes. To investigate the binding of PPARγ and RXR to PPREs, three mutations were constructed in the DNA-binding domains of PPARγ; two of the mutants maintained the structure of zinc finger I (PPARγ-GS and PPARγ-AA), and a third mutation disrupted the protein structure of zinc finger I (PPARγ-CS). Results indicated that the mutations of PPARγ that maintained intact zinc fingers were capable of binding to a variety of PPREs in the presence of RXR and could activate transcription on several PPREs. In parallel, a mutation was created in the DNA-binding domain of RXRα that maintained the structure of the zinc fingers (RXR-GS) but did not bind DNA and was transcriptionally inactive. Examination of the 3′ half-site of several PPREs revealed that variations from the consensus sequence reduced or abolished transcriptional activity, but conversion to consensus improved transcriptional activity with PPARγ-GS and PPARγ-AA. Examination of the 5′ half-site indicated that the upstream three nucleotides were more important for transcriptional activity than the downstream three nucleotides. Our data demonstrated that stringent binding of RXR to the 3′ half-site of a PPRE is more influential on the binding of the PPARγ/RXR heterodimer than the ability of PPARy to bind DNA. Thus, unlike RXR, PPARγ exhibits promiscuity in binding on a PPRE, suggesting that the definition of a PPRE for PPARγ may need to be expanded.
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U2 - 10.1074/jbc.M411422200
DO - 10.1074/jbc.M411422200
M3 - Article
C2 - 15572375
AN - SCOPUS:13544249591
VL - 280
SP - 3529
EP - 3540
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 5
ER -