Down-regulation of COUP-TFII by Notch pathway proteins in LECs. (A) Expression of COUP-TFII protein in LECs that were transiently transfected with a control vector (CTR, pcDNA3) or vectors expressing human NICD (hNICD, pcDNA3-hNICD), mouse Hey1 (mHey1, pcDNA3.1 HERP2FLAG), human Hey1 (hHey1, pcDNA-hCHF2), or mouse Hey2 (mHey2, pcDNA3.1 HERP1FLAG). None indicates untransfected LECs. (B) Expression of COUP-TFII mRNA was determined by quantitative RT-PCR in LECs that were transduced with a control (AdCTR), Hey1 (AdHey1), and/or Hey2 (AdHey2) adenovirus after 48 hours. Data are mean ± SD relative to the value of AdCTR. (C) Repression of COUP-TFII promoter activity by human NICD and Hey1. Mouse COUP-TFII promoter luciferase constructs were cotransfected with a control (CTR), Hey1, or NICD vector into HEK293 cells for 48 hours, and the promoter activity was determined by luciferase activity that was normalized with the amount of whole cell lysate used. pGL3 indicates pGL3-Basic vector (Promega). Data are relative luciferase activity ± SD.