FIGURE 4:

Changes in the levels of occludin 3′-UTR luciferase reporter activity after deletion of CUGBP1-binding sites. (A) Activity of various pLuc-occludin 3′-UTR luciferase reporters with or without CUGBP1-binding site in cells overexpressing CUGBP1. Top panels, schematic of firefly luciferase reporter constructs containing full-length (FL) or different fragments (F) of the occludin 3′-UTR. BS, CUGBP1-binding site. Twenty-four hours after the cells were transfected with either CUGBP1 expression vector or control vector, the cells were further transfected with each of various occludin 3′-UTR luciferase reporter constructs and a Renilla luciferase control reporter. The levels of firefly and Renilla luciferase activities were assayed 24 h later. The results were normalized to the Renilla luciferase activity and are shown as the means ± SEM of data from three separate experiments. * p < 0.05 compared with cells transfected with control vector. (B) Activity of various pLuc-occludin 3′-UTR luciferase reporters after CUGBP1 silencing. Cells were initially transfected with either siCUGBP1 or C-siRNA for 24 h and then with each of various occludin 3′-UTR luciferase reporter constructs in cotransfection with the Renilla luciferase reporter. * p < 0.05 compared with cells transfected with C-siRNA. (C) Effect of deletion of specific CUGBP1-binding site (schematic) in occludin 3′-UTR on luciferase reporter activity after CUGBP1 overexpression or CUGBP1 silencing. * p < 0.05 compared with cells transfected with control vector or C-siRNA.