FIG. 3.

DNase I footprinting shows selectively binding of TFIIIC to the promoter in a chromatin template. Aliquots (containing 2 fmol) of DNA and chromatin samples used in the transcription reactions were incubated with TFIIIC at 30°C for 30 min prior to DNase I digestion and primer extension analyses. (A) Lanes 1 to 4, sequencing ladder of DNA template; lane 5, DNA alone; lane 6, DNA plus 100 ng of TFIIIC; lane 7, chromatin template alone; lane 8, chromatin with 100 ng of TFIIIC. (B) Lane 1, chromatin template alone; lanes 2 and 3, chromatin plus 100 ng or 200 ng of TFIIIC; lanes 1′ to 3′, longer exposure of lanes 1 to 3 to more clearly show the footprint over the tRNA gene. Arrows indicate the hypersensitive sites generated upon binding of TFIIIC. Positions of the A box, B box, termination sequences, and transcription start site are depicted on the left.