Ets transcription factor binding sites are necessary for promoter activity. (A) Nucleotide sequence of the conserved proximal promoter region in which the predicted E box, Ets sites, and other conserved sequence blocks are marked. Nucleotides in the alignment are shaded in gray if they are conserved at that position in more than 70% of the sequences, in dark gray if conserved in more than 85% of the sequences, or in black if they are identical in all sequences. Species included in the multiple sequence alignment are as described in Figure 1. (B) Reporter assays of a series of proximal promoter mutation constructs in which the predicted transcription factor binding sites were ablated. Constructs were transfected into MS1 and 416B cells as described in Figure 3. • indicates E box motif; , Ets motif; and ○, unknown motif.

indicates motifs mutated in the various constructs.