Figure 6

Reintroduction of PS1 into PS1−/− endothelial cells leads to decreased fibronectin expression. PS1−/− endothelial cells (p41), grown to confluency were trypsinized, resuspended in electroporation buffer and electroporated with a plasmid carrying the human PS1 cDNA or empty vector. In panel A, the expression of fibronectin was analyzed 48 hrs post-electroporation by Western blotting on cell lysates. 10 μg of protein was loaded per lane. Blots were sequentially probed for fibronectin (FN), and β-tubulin (β-tub). The expression of PS1 was determined with an antibody (NT.1) that is specific for the human (hPS1) N-terminal fragment of PS1 (NTF). The amount of electroporated cDNA (μg) is indicated above each lane. Mock-transfected cells were electroporated with 40 μg of empty vector. In panel B, the experiment in panel A is quantitated. A Pearson correlation coefficient showed that there was a significant negative correlation between the amount of PS1 plasmid transfected and the level of expression of fibronectin (R²=0.8584; p=0.0237). This experiment was replicated twice using transfections of 20 μg of PS1 cDNA or empty vector.