FIGURE 5.

DR8, IR0, but not DR0 act as RAREs. A, shown is a schematic representation of the reporter vector where three copies of the indicated motifs spaced by 12 nucleotides are inserted upstream of a TATA element and the CAT reporter gene. B, shown is relative CAT activity of the different reporter vectors 48 h after transfection. EV is empty vector, and the elements in the other vectors are shown below each lane. The DR5 is from the Rarb gene, DR0 is from the Socs3 gene, the IR0 is from the Trim16, gene, DR0 (P) is the pseudo-DR0 motif from the Hoxb13 locus, DR8 (C) is the composite DR8 element from the Mafa gene, and DR8 is the simple DR8 from the Dedd gene. C, relative CAT activity from a second series of transfections shows the activity of the mutated composite Mafa DR8 element. Wt, wild-type; Mt, mutant.