Figure 7.

NPX1 interacts with TIP and represses the transcription activity of TIP in yeast. A, Interaction analysis of NPX1 using the yeast two-hybrid system. The yeast strain MaV203 was cotransformed as indicated. PC, Positive control (BD-Krev1 and AD-RalGDS-wt were used); NC, negative control (BD-Krev1 and AD-RalGDS-m2 were used). Activation of HIS3 and lacZ is indicated by growth on −His medium and by the blue color, respectively. White colonies indicate a lack of reporter activation. B, NPX1 represses the activity of TIP. BD-NPX1 represses the activity of TIP in yeast, as indicated by the decreased β-galactosidase (β-gal) activity. BD-TIP but not NC (cotransformants of pGBKT7 and pDEST 32 vector) and BD-NPX1 activate lacZ expression. Data represent means ± sd of three independent experiments. Different letters indicate significant differences between means at P < 0.05 (Student's t test). OD, Optical density.