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. Author manuscript; available in PMC: 2009 Apr 10.
Published in final edited form as: Mol Cell. 2008 Oct 10;32(1):96–105. doi: 10.1016/j.molcel.2008.09.009

Figure 2. TAF3 is required for MyoD-dependent activated transcription of Myogenin.

Figure 2

A. Luciferase reporter assay to determine the Myogenin promoter response to the activator MyoD. Diagram of the reporter constructs transfected into 3T3 fibroblast cells. For this reporter assay, pGL3 vector control sequences alone or pGL3 vector containing the endogenous Myogenin promoter sequences (184 bp fragment) were used to drive the expression of luciferase. Constructs were introduced into fibroblast cells in the presence or absence of exogenous FLAG-MyoD. Luciferase expression was determined and plotted as fraction relative to total protein (luciferase/ug protein). Each bar represents the mean of triplicate samples per condition. The error bars represent the standard deviation. Protein immunoblot analyses were performed to determine relative levels of transfected FLAG-MyoD in fibroblast cells. B. TAF3 is required to potentiate MyoD-dependent transcription activation of Myogenin in vitro. Silver stain of the myogenic activator FLAG-MyoD co-expressed with its heterodimer E47 were affinity purified from insect cells using anti-FLAG antibody. This purified factor was included in our purified in vitro reconstituted transcription system to test the effects of activator in TRF3- or TAF3/TRF3-mediated transcription reactions. Using conditions described in Figure 1C, TRF3- or TAF3/TRF3-mediated transcription reactions were supplemented with the purified activator MyoD/E47 in vitro. The arrow indicates specific transcription products analyzed by primer extension.