The proximal VWF promoter spanning nucleotides +53/+240 can repress the heterologous SV40 promoter in VWF-producing and non–VWF-producing cells. (A) Diagrammatic representation of the VWF promoter region cloned upstream of the SV40 promoter and luciferase reporter gene. Nucleotide sequences, GATA and Ets sites, and transcriptional start site are indicated as outlined in Figure 1. (B) The mean normalized luciferase expression relative to a “No insert” control pGL2 construct is graphed as a percentage. The number (n) of experiments carried out is indicated on each graph. The error bars indicate the standard error of the mean. Statistical differences between each deletion construct and the pGL2 control construct were assessed using a Student t test, and a P value of less than .05 is considered significant.