FIG. 6.

Expression of cyclin D1 T286A does not completely alleviate the PTEN-mediated repression of RNA Pol I-dependent transcription. (A) The expression of cyclin D1 T286A does not reverse the repression of RNA Pol I-dependent transcription by PTEN. PTEN-inducible U87 cells were cotransfected with cyclin D1 T286A expression vector or empty vector and PrHuCAT. Cells were treated with 1 μg/ml DOX as designated. Total RNA was isolated, and RNA Pol I promoter activity was measured. The values shown are means ± SEM from three independent determinations. (B) Expression of cyclin D1 T286A in transfected U87 cells. Cells were transfected as described for panel A, and protein lysates were prepared and subjected to immunoblot analysis. Membranes were probed with either actin or Flag antibodies to detect the Flag-tagged cyclin D1 T286A, as designated.