Table 1.

Types of transcriptional responses observed following ligand activation of PPARβ/δ in mouse primary keratinocytes

Type	Without exogenous ligand	With exogenous ligand
I	Repression	–
II	Activation	–
III	–	Activation
IV	–	Repression
V	Repression	Activation
VI	Activation	Repression
VII	Activation	Activation
VIII	Repression	Repression

The effect without exogenous ligand reflects the response in expression of a particular gene observed in control Pparβ/δ-null keratinocytes as compared to control wild-type keratinocytes. For this column, repression indicates that gene expression is higher in Pparβ/δ-null cells as compared to wild-type cells and activation indicates that gene expression is lower in Pparβ/δ-null cells as compared to wild-type cells. The effect with exogenous ligand reflects the response in expression of a particular gene observed in wild-type keratinocytes treated with the highly specific PPARβ/δ ligand GW0742 as compared to control wild-type keratinocytes. For this column, activation indicates that gene expression is higher in GW0742-treated wild-type cells as compared to control wild-type cells and repression indicates that gene expression is lower in GW0742-treated wild-type cells as compared to control wild-type cells.