Figure 2.

 The position of the DPE relative to the Inr is important for transcriptional activity and TFIID binding. (A) In vitro transcription analysis of wild-type and mutant Drosophila joc promoters. A series of mutant joc core promoters (comprising sequences from −3 to +48 relative to the RNA start site) was constructed in which the spacing between the DPE and the Inr was either increased or decreased by 3-nucleotide increments, as depicted. These templates were transcribed in vitro with the Drosophila SK nuclear extract, and the resulting transcripts were subjected to primer extension analysis. The positions of the reverse transcription products from each template are indicated by arrows. Transcriptional activity from the +1 start site for each template is reported as relative to that of the wild-type joc promoter (joc WT). (B) DNase I footprinting analysis of the binding of TFIID to the joc promoter. The mutant versions of the promoter contained either a 3-nucleotide deletion (joc −3) or a 3-nucleotide insertion (joc +3) between the Inr and DPE elements, as in A. The amount of purified Drosophila eTFIID in each reaction is indicated. The positions of the Inr and DPE elements in the mutant promoters are depicted at each side of the autoradiograph.