FIG. 9.

Expression of either of the DN forms of PI 3-kinase potently suppresses bFGF induction of cyclin D1 protein in wild-type NIH 3T3 cells. Cells were cotransfected with 1.5 μg each of pSV-βgal and either an empty vector or an expression plasmid for DNp110, BDKD, or DNp85, made quiescent, and then stimulated with bFGF for 9 h. The percentages of cyclin D1-positive cells in transfected population were 69.8 ± 5.1, 32.7 ± 1.4, 25.7 ± 2.2 and 20.3 ± 3.8 for vector control, DNp110, BDKD and DNp85-expressing cells, respectively (means ± SE of three determinations).