The PPAR gamma gene extends over 100kb with 9 exons which gives rise to 3 different PPAR gamma transcripts with differential promoter usage and differential splicing: PPAR gamma 1, 2 and 3. PPAR gamma 1 transcript contains 8 exons which is 97% identical to PPAR gamma 2.

According to Entrez-Gene, PPAR gamma gene maps to NC_000003 and spans a region of 100 kilo bases. According to Spidey, PPAR gamma 1 has 8 exons, the sizes being 171, 74, 228, 170, 139, 200, 451 and 459 bps. PPAR gamma 2 has 7 exons, the sizes being 173, 228, 170, 139, 200, 451 and 459. PPAR Gamma 3 has 8 exons, the sizes being 198, 74, 228, 170, 139, 200, 451, and 459.

PPAR gamma 1 mRNA (NM_138712) has a size of 1892 bp, PPAR gamma 2 mRNA (NM_015869) has a size of 1820 bp while PPAR gamma 3 mRNA (NM_138711) has a size of 1919 bp.
The ratio of PPAR gamma2 to PPAR gamma1 transcript has been shown to increase in obese patients in correlation with their body mass indices. A low calorie diet was specifically shown to down-regulate the expression of PPAR gamma2 mRNA in adipose tissue of obese humans. However, this effect was lost subsequently during weight maintenance.
The PPAR gamma3 mRNA is transcribed from a novel promoter localized 5 of exon A2 (see diagram above). PPARgamma3 mRNA expression is said to be restricted to human white adipocytes, as well as in HepG2, Caco-2 and HeLa cell lines.

No pseudogene has been reported for PPAR gamma.

There are 3 different PPAR gamma proteins PPAR gamma 1, 2 and 3 which differ at their 5-prime ends, each under the control of its own promoter. PPAR gamma1 and PPAR gamma3, however, give rise to the same protein, encoded by exons 1 through 6, because neither the A1 nor the A2 exons are translated.

The PPAR gamma protein consists of 505 amino acids and has a molecular weight of 57.6 kDa. According to the NCBI conserved domain search, it contains two C4 type zinc finger domains. In nearly all cases, this is the DNA binding domain of a nuclear hormone receptor. In addition it contains a ligand binding domain. This all-helical domain is involved in binding the hormone to these receptors.

In general, the highest expression of PPAR gamma can be found in the adipose tissue, colonic epithelia, macrophages, and endothelium, followed by the kidney, liver, and small intestine; whereas PPAR gamma can barely be detected in the muscle.
Of the splice variants, PPAR gamma1 and gamma2 are expressed in adipose tissue. PPAR gamma1 expression levels were lower than gamma2 in the liver and heart, whereas both gamma1 and gamma2 were expressed in skeletal muscle at low levels.
The expression of PPAR gamma3 mRNA is restricted to adipose tissue and differentiated CaCo2 cells.

Localized in the nucleus.

Protein-protein interactions PPARs function as heterodimers with retinoid receptor (RXR). The PPAR RXR heterodimer function along with co-activators such as NCOA6, NCOA7 or PPARBP, leading to increases in transcription of target genes. PPAR gamma1 or PPAR gamma 2 in a heterodimer with RXR is capable of forming complexes with oligonucleotides containing peroxisome proliferator response elements (PPREs) usually 5-AACT AGGNCA A AGGTCA-3 in the promoter regions of the target genes. PPAR gamma1 and PPAR gamma2 can also form complexes with RXRB and RXRG. Ligands of PPAR gamma PPAR gamma1 and PPAR gamma2 have ligand-dependent and -independent activation domains. Due to the presence of an additional 28 amino acids at the amino terminus, PPAR gamma2 has a ligand-independent activation domain that is several folds more effective than that of PPAR gamma1. However, in the presence of ligands that can be lipid derivatives, eicosanoids, xenobiotics etc, triggers a conformational change in the protein that results in the recruitment of transcriptional co-activators. In the absence of a ligand, PPAR gamma is bound to transcriptional co-repressors containing nuclear receptor corepressor ( N-CoR ) and can actively silence the transcription of target genes. Phosphorylation of serine 112 at the N terminus of PPAR gamma2 results in a reduction of its transcriptional activity. This phosphorylation further promotes the sumoylation of lysine 107 which then further reduces its transcriptional activity.
The prostaglandin J2 (PGJ2) metabolite l5-deoxy-Delta12,14-PGJ2 binds directly to PPAR gamma and can promotes the differentiation of C3HlOT1/2 fibroblasts to adipocytes. Its principal function came to light when it was found that the anti-diabetic drug thiazolidinediones (TZD) was a PPAR gamma ligand. The TZD series of drugs via their agonist activity on PPAR gamma promotes the uptake of circulating fatty acids into adipocytes. The glucose lowering effects of TZDs are due to increased disposal of glucose into adipose tissues along with increased expression of insulin sensitizing factors (such as adiponectin) and decreased expression of proteins that promote insulin resistance.
PPAR gamma also has an anti-inflammatory role by inhibiting the production of inflammatory cytokines, and other proteins such as TNF-alpha, MMP9 and iNOS from macrophages in the presence of ligands such as TZD. Inhibition of pro-inflammatory transcription factors such as NF-kB, AP-1 and STAT by PPAR gamma is said to be through limited availability of shared co-factors as well as direct protein-protein interactions.

Canis familiaris PPARG peroxisome proliferator-activated receptor gamma
Pan troglodytes PPARG peroxisome proliferator-activated receptor gamma
Rattus norvegicus Pparg peroxisome proliferator-activated receptor gamma
Mus musculus Pparg peroxisome proliferator-activated receptor gamma

Several mutations in the PPAR gamma protein have been reported along with their association with diseased states.
1. P115Q results in severe obesity
2. 1-BP DEL, 472A, Q286P, K319TER and R288H mutations have been reported in somatic colon cancer
3. P467L, V290M mutations have been reported in partial familial lipodystrophy type 3
4. 3-BP DEL/1-BP INS, NT553, shown in digenic insulin resistance.