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. 2008 Apr 10;36(9):3118–3127. doi: 10.1093/nar/gkn163

Figure 2.

Figure 2.

The TFIIB aptamers fall into two classes based on their ability to interfere with TFIIB–TBP interaction. (A) Complexes were assembled on labeled TATA DNA with yeast TBP (20 nM), TFIIA (0.5 nM) and TFIIB (200 nM) in the presence or absence of the TFIIB aptamers (800 nM). Class I aptamers (B2, B60, etc.) compete effectively and prevent formation of the TATA–TBP–TFIIA–TFIIB (DAB) complex, whereas Class II aptamers (B4, etc.) were not as efficient. The lighter band seen migrating slightly faster than the DAB complex in the ytRNA lane is most likely due to dissociation of the complex during electrophoresis. (B) The Class I aptamers instantaneously disrupt the preformed DAB complex by removing TFIIB (leaving the DA complex intact), whereas the Class II aptamers had no such effect. The ‘yt’ represents a yeast tRNA which is used as a control RNA. In the lanes marked by the box, excess cold DA was added to the DAB complex to verify that the DAB complex is stable for the time frame of the disruption and competition experiments.