Figure 1.

Testing the RE classification scheme on natural DR1-type sequences. The average binding strength of in vitro translated PPAR-RXR heterodimers to DR1-type PPREs was determined by gelshift assays in reference to the consensus PPRE AGGTCAAAGGTCA, including all categories (that is, combinations of the classes I, II and III) that resulted in an average binding of at least 1%. Variations from the consensus PPRE are highlighted in green for PPARα, in dark blue for PPARγ and in light blue for PPARβ/δ. In total, the in vitro binding data of 136 different REs were used (the non-binding DR1-type REs are shown in Additional data file 1), with a minimum of six sequences for each category. SD, standard deviation.