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. 2004 Feb 17;101(8):2548–2553. doi: 10.1073/pnas.0308655100

Fig. 6.

Fig. 6.

Effect of F-spondin on APP-dependent transactivation of Gal4-Tip60-mediated transcription. (A) F-spondin inhibits APP-dependent transactivation. A constant amount of Gal4-Tip60, Fe65, and APP was cotransfected with increasing amounts of Ig-F spondin. Note that, without F-spondin, APP causes a strong stimulation of Gal4-Tip60-dependent transcription as described (7). F-spondin dramatically inhibits APP-dependent transactivation of transcription by Gal4-Tip60, such that even low concentrations of F-spondin (<100 ng of transfected plasmid) almost completely block the response. (B) Comparison of the effects of multiple Ig-fusion proteins on the APP-dependent transactivation of Gal4-Tip60. All proteins were expressed with 50 ng of cotransfected plasmids. (C) Increasing concentrations of APP are unable to rescue the F-spondin-dependent inhibition of APP-dependent transactivation of Gal4-Tip60. Constant amounts of Gal4-Tip60, Fe65, and Ig-C, Ig-N1β-1, or Ig-F spondin were cotransfected with increasing concentrations of APP. The bell-shaped dose–response curve under control conditions as reported (7) is probably due to dilution of transcription factors by increasing amounts of APP. Nevertheless, even at high concentrations of APP, F-spondin induces a relative inhibition of transactivation.