FIG. 1.

Transforming potential of R-Ras effector loop mutants. (A) Schematic representation of R-Ras effector loop mutants and the corresponding region of H-Ras. Amino acid changes are indicated by italics. (B) The transforming ability of different R-Ras effector loop mutants was assayed with NIH 3T3 cells by transfecting 100 ng of R-Ras S61, G63, and C66 mutants. Parallel cultures were transfected with the same amount of the parental R-Ras L87 plasmid (WT) or an empty vector (Neo) as a negative control. Two representative sets of results from four independent experiments are shown. (C) Focus morphology of NIH 3T3 cells transfected with R-Ras effector loop mutants was examined after 3 weeks in culture by Giemsa stain. (D) The expression levels of different R-Ras effector loop mutants were assessed by Western blot (WB) analysis with cell lysates derived from marker-selected mass cultures.