Figure 2.

Transcriptional activation by the nonnatural coactivators L-1 and D-1. (A) The reporter construct pG₅E4T contains five tandem 17-bp GAL4 binding sites (indicated by open boxes) positioned 23 bp upstream to the TATA box of a E4 promoter gene. (B) The template pG₅E4T was transcribed in a crude HeLa cell nuclear extract in the presence of various added proteins and artificial coactivators (illustrated as in Fig. 1, except green sphere represents FK506). The primer and the E4 extension products are indicated by arrows. (C) Quantitation: The autoradiogram in B was scanned by PhosphorImager and the transactivator’s activity were plotted relative to the activity of the control nuclear extract.