Sequence of the PRNP promoter and expression analysis of 5' deletion constructs. (A) Schematic representation of the PRNP promoter from position -1593 to +134 relative to the putative transcriptional start site (+1) . The positions of relevant restriction sites used for deletion analysis are indicated. (B) Sequence of the proximal PRNP promoter from position -203 to +1. The positions of relevant restriction sites and nuclear factor binding domains prpA and prpB are delineated by brackets. (C) PRPN promoter activities in HeLa cells as determined by transient transfection. The full-length (FL) promoter construct (column 1) represents the sequence from position -1593 to +134 as indicated in A. The remaining 5' deletions (columns 2-10) were introduced at the restriction sites as shown in A and B. CAT activities were normalized to identical β-galactosidase activities. The activity of each deletion was expressed relative to the activity of the full-length promoter construct (100%). Each column shows the average value of 8-10 independent experiments with standard deviation.