Summary of the relative luciferase activities of reporter constructs containing various parts of DNA region +5.8 in the ABO gene. Transient transfection experiments were performed using reporter plasmids in which various parts of region +5.8 were subcloned upstream of the ABO promoter sequence. Below the map of restriction enzyme sites with positions relative to the translation start site of exon 1, region +5.8 is subdivided into regions A through F. Construct names are indicated to the left of the square, and the locations of the fragments that were inserted upstream of the ABO promoter sequence in a direction opposite to that of the promoter are shown. Arrows to the left represent the inserts oriented in a direction opposite to that of the promoter. The v-shaped segment represents deleted sequences. The +5653 to +6154 sequence (subregion C) is indicated by solid box with an arrow. Each construct as depicted on the left was transiently transfected into K562 cells and the luciferase activity obtained was normalized, as shown in the right panel. To facilitate comparison of the corresponding reporter activity of each construct, the activity of reporter plasmid SN was assigned an arbitrary value of 1.0. The results are expressed as an average of the relative activity observed. The mean values and SDs were calculated from more than 3 independent experiments.