FIG. 3.

Specificity of protein interactions with the TNF-α 3′ UTR. EMSAs were performed as described for Fig. 1 and 2, using a full-length human TNF-α 3′ UTR probe and 10 μg of cytoplasmic extract from LPS-stimulated RAW264.7 cells. Competitor RNA was added to the binding reaction mixtures 20 min prior to the addition of labeled probe. (A) Protein interactions with specific RNA competitors present, as indicated, in 1- to 100-fold molar excess over the probe. (B) Protein interactions with poly(U) or poly(A) RNA present, as indicated, in 1- to 1,000-fold excess (by mass) over the probe.