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. 2009 Apr 1;4(4):e5103. doi: 10.1371/journal.pone.0005103

Figure 7. Transcription from X mRNA Start site 2 requires MED26-containing mediator and TFIIB but not Gcn5.

Figure 7

(A) HeLa cell nuclear extract (NE) was immunodepleted with control or anti-Gcn5 antibody. The depleted NEs were then tested for the level of depletion by western blotting and for X gene transcription activity from the two start sites using the enhancer-X promoter construct. (B) HeLa NE was immunodepleted with control or anti-MED26 antibody. The depleted NEs were then tested for the level of depletion and for X gene Start site 2 transcription activity using either the enhancer-X promoter construct or the minimal promoter construct in the absence (lane 2) or presence (lanes 3 and 4) of mediator complexes purified from P.5 (lane 3) or P1.0 (lane 4) phosphocellulose fractions. The response of the transcription from Start site 1 has been reported [6]. (C) HeLa NE was immunodepleted with control or anti-TFIIB antibody. The depleted NEs were then tested for depletion and for X gene transcription activity from the two start sites using the enhancer-X promoter construct in the absence (lane 2) or presence (lanes 3–5) of the purified TFIIB (10, 30, or 100 ng).