Figure 4

Expression from the APP promoter with mutations within the 5'- APP -UTR. (A) Transient transfection in HeLa cells. The activities of consecutive 5-base-pair block mutations M [106-110]-M [86-90](columns 2-5) are presented as CAT activities relative to the wild type APP [147] construct (column 1), which was assigned the value of 100%. In addition to the original M [96-100] mutation (column 4, *) [see Fig. 3D for sequence], the activities of two additional mutations (column 4, ** and ***) that removed the ATG sequence were investigated. The results represent the average values of at least ten separate transfections with standard deviations (error bars). (B) Run-off in vitro transcription in HeLa cell nuclear extract with the same designations as in A. (C) CAT RNA levels in HeLa cells transfected with constructs APP [147] WT (column 1), M [101-105] (column 2), and M [96-100] (column 3) were determined by quantitative RT-PCR. The wild type APP [147] construct (column 1) was assigned the value of 100% and the results represent the average of four independent experiments with standard deviations (error bars).