Factor interactions at simian virus 40 GC-box promoter elements in intact nuclei.

Abstract Primer extension footprinting was used to probe late simian virus 40 regulatory elements in intact infected cell nuclei. Specific protection was observed over the viral "GC-box" transcription elements. The participation of the bound templates in gene activation is addressed by quantitation that shows that their abundance greatly exceeds that of transcription complexes but is comparable to that of open chromatin.