Figure 2.

Stable preinitiation complex formation is rapid. (A) Transcription reactions were assembled, initiated, and stopped according to the procedure diagrammed at the top of the figure. At varying time points after the addition of AdMLP, 20-μl aliquots were removed and added to ctDNA and nucleotides to produce a 390-nt G-less transcript. The star indicates an internal start site within the G-less cassette. (B) Stable preinitiation complexes form within 10 s. Reactions were carried out as in A.