Imagine that you've run a DNA footprinting analysis.Many closely spaced bands (DNA fragments)are seen in the lane of the gel prepared from DNA without protein.In the adjacent lane prepared from DNA mixed with protein,a subset of the bands is seen,but there is a large region where no bands are observed.This empty region represents
A)the region where protein did not bind to DNA.
B)the region where protein bound to DNA.
C)a region where there was no DNA for protein binding.
D)a region where protein was digested by the enzyme.

Question

Quizplus · Accepted Answer

The empty region where no bands are observed in the lane prepared from DNA mixed with protein represents the region where protein bound to DNA. The absence of bands indicates that the protein protected that region of DNA from digestion by the footprinting agent. The subset of bands that is seen in this lane represents the regions where the protein did not bind or caused weaker protection of the DNA, allowing the footprinting agent to digest the DNA and produce fragments visible as bands. The presence of closely spaced bands in the lane of the gel prepared from DNA without protein indicates that the DNA was accessible to the footprinting agent and there were no specific protein-binding sites in that region.

Imagine That You've Run a DNA Footprinting Analysis