Method for identifying or screening agonist and antagonist to PPAR

A method for identifying or screening an agonist for, or an antagonist to, a human peroxisome proliferator-activated receptor gamma (PPARγ), which comprises contacting a test cell with a substance to be tested, and detecting a change in a ligand-dependent interaction between the human PPARγ and a coactivator due to the substance to be tested, by measuring the expression of a reporter gene as an index, wherein the test cell contains:

• (i) a first extrinsic fused gene coding for a first fused protein comprising a ligand binding domain of human PPARγ and a first domain of a transcription factor, wherein the first domain of said transcription factor being a DNA binding domain or a transcriptional activation domain;
• (ii) a second extrinsic fused gene coding for a second fused protein comprising a human PPARγ binding domain of a coactivator which interacts with the human PPARγ and a second domain of the transcription factor, wherein the second domain of said transcription factor is a transcriptional activation domain when the first domain of the transcription factor is a DNA binding domain or is a DNA binding domain when the first domain of the transcription factor is a transcriptional activation domain;
• and
• (iii) a response element to which the DNA binding domain of said transcription factor can bind and a reporter gene linked hereto, and
• wherein the ligand hinding domain of human PPARγ comprises residues 174 to 475 of SEQ ID NO:6.

A method for identifying or screening an agonist for, or an antagonist to, a human peroxisome proliferator-activated receptor gamma (PPARγ), which comprises contacting a test cell with a substance to be tested, and detecting a change in a ligand-dependent interaction between the human PPARγ and a coactivator due to the substance to be tested, by measuring the expression of a reporter gene as an index, wherein the test cell contains:

• (i) a first extrinsic fused gene coding for a first fused protein comprising a ligand binding domain of human PPARγ and a first domain of a transcription factor, wherein the first domain of said transcription factor being a DNA binding domain or a transcriptional activation domain;
• (ii) a second extrinsic fuses gene coding or a second fused protein comprising a human PPARγ binding domain of a coactivator which interacts with the human PPARγ and a second domain of the transcription factor, wherein the second domain of said transcription factor is a transcriptional activation domain when the first domain of the transcription factor is a DNA binding domain or is a DNA binding domain when the first domain of the transcription factor is a transcriptional activation domain;
• and
• (iii) a response element to which the DNA binding domain of said transcription factor can bind and a reporter gene linked thereto, and wherein human PPARγ comprises the amino acid sequence of SEQ ID NO:6.

A method for screening or identifying an agonist for, or an antagonist to, a human peroxisome proliferator-activated receptor gamma (PPARγ), comprising:

• contacting a test cell containing a two-hybrid system for detecting a ligand-dependent interaction between human PPARγ and CREB-binding protein (CBP) with a substance to be tested;
• detecting a ligand-dependent interaction between human PPARγ and CBP in the test cell due to the substance to be tested;
• and
• measuring the effect of the substance to be tested on the ligand-dependent interaction to screen and identify a substance that is an agonist for, or an antagonist to, a human PPARγ.