In VIVO Footprinting

The revolution in biological research initiated by the demonstration that particular DNA molecules could be isolated, recombined in novel ways, and conveniently replicated to high copy number in vivo for further study, that is, the recombinant DNA era, has spawned many additional advances, both methodological and intellectual, that have enhanced our understanding of cellular processes to an astonishing degree. As part of the subsequent outpouring of information, research exploring the mechanisms of gene regulation, both in prokaryotes and eukaryotes (but particularly the latter), has been particularly well represented. Although no one technical approach can be said to have brought the filed to its current level of sophistication, the ability to map the interactions of trans-acting factors with their DNA recognition sequences to a high level of precision has certainly been one of the more important advances.This footprinting approach has become almost ubiquitous in gene regulatory studies; however, it is in its