(A) Effect of Pggt1b deficiency on the proliferation of primary mouse fibroblasts. Equal numbers of β-gal– and Cre-adenovirus–treated primary Pggt1b^fl/+ and Pggt1b^fl/fl fibroblasts were seeded on 12-well plates. On days 0, 1, 2, and 5, the cells were trypsinized and counted. Values are mean of 1 cell line assayed in duplicate. Similar results were obtained in 2 experiments with 2 different Pggt1b^fl/+ and Pggt1b^fl/fl cell lines. (B) Upper panels: β-gal– and Cre-adenovirus–treated Pggt1b^fl/fl cells from the experiment described in A. Lower panels: cells from the experiment in A stained with phalloidin (red) to visualize polymerized actin and with DAPI (blue) to visualize DNA. Original magnification, ×10 (top); ×63 (bottom). (C) Migration of β-gal– and Cre-adenovirus–treated fibroblasts. Values are mean ± SEM of 2 cell lines assayed in triplicate. P < 0.01 at 8 and 24 hours, P < 0.0001 at 48 hours compared with β-gal. (D) Western blot of extracts from β-gal– and Cre-adenovirus–treated primary Pggt1b^fl/fl, Pggt1b^fl/flK^LSL, and Pggt1b^fl/+K^LSL fibroblasts. (E) Effect of Pggt1b deficiency on the proliferation of K-RAS^G12D–expressing primary fibroblasts. Equal numbers of β-gal– and Cre-adenovirus–treated primary Pggt1b^fl/+K^LSL and Pggt1b^fl/flK^LSL fibroblasts were seeded in 12-well plates. On days 0, 1, 2, 4, and 6, the cells were trypsinized and counted. Inset shows genotypes of cells assessed by PCR amplification of genomic DNA (lane 1, Pggt1b^fl/+K^LSL; lane 2, Pggt1b^Δ/+K^G12D; lane 3, Pggt1b^fl/flK^LSL; lane 4, Pggt1b^Δ/ΔK^G12D). Values are mean of 1 cell line assayed in duplicate. Similar results were obtained in 2 experiments with 2 cell lines per genotype. (F) Photographs of fibroblasts from the experiment described in E. Original magnification, ×10. (G) Cell-cycle analysis of β-gal– and Cre-adenovirus–treated Pggt1b^fl/flK^LSL fibroblasts. The experiment was repeated twice with similar results. PI, propidium iodide.