Structure, relationship and splice variants of the PPARs. A) Schematic diagram of the structure common to nuclear hormone receptors and the PPARs, indicating the relative similarities between the various regions of PPAR isotypes across species   . B) Schematic of the splice variants of the PPARs. Schematic of PPARα adapted from   . The diagram of PPARδ splice variants was adapted from . Exons IA, IB, IC, ID, and 2 are non-coding. Regarding PPARγ splice variants, exons 1–6 are common to all PPARγ subtypes. PPARγ1 includes the untranslated exons A1 and A2, PPARγ2 contains the translated exon B, PPARγ3 contains the untranslated exon A2, PPARγ4 contains only exons 1–6 (adapted from   ). Images not drawn to scale.