Fig 4.

Knockdown of β-catenin and TCF-4 induces transcription of stably integrated LTR in astrocytes. Stably integrated LTR-Luc was developed in U87MG and U251MG cells as described in Materials and Methods. (a) Stably transfected U87MG cells were grown for the indicated number of passages, and firefly luciferase activity was assayed in each passage. Data points represent luciferase readings from at least two independently generated LTR-Luc lines, with luciferase readings taken in duplicate and normalized to total protein content. (b and c) U87MG-HIV-LTR-LUC and U251MG-HIV-LTR-LUC cells were transfected with the indicated siRNAs. After 72 h, cells were lysed and assayed for luciferase activity. Experiments were performed in duplicate at least three times. *, P < 0.05 in comparison with a scrambled siRNA negative control (NC).