Kornberg’s work is a great contribution to chromatin remodeling.  Remodeling of chromatins is required for transcription.  Chromatins are bound tightly and wound around nucleosomes.  By removing nucleosomes (composed of histones and other proteins), this exposes the promoter for transcription.  There was evidence presented that the removal of a nucleosome from the TATA box of a promoter, was seen by the sliding of the histone octamer to an adjacent position [21]. Further test, using DNA footprinting, was able to show that bound histones do not do not allow cleavage of DNA by DNAse. On the other hand, unbound DNA was shown to produce nicks in the presence of DNAse.

By understanding how transcription works, histone mobility can be understood as well.  The movements of nucleosomes from promoter sites require energy and this energy is supply by the hydrolysis of ATP.  A recent study in yeast showed that chromoatin-remodeling complexes (SWI/SNF) are ATP dependent.  As the RNA polymerase moves down the chromatin, the histones are pushed away to exposed the next few nucleotides. Two types of perturbation were considered and they are DNA twisting and bending.  The study suggest that DNA bends instead of twisting in the movement of nucelosomes [22].  Remodeling of chromatin is very important, and must occur to allow transcription.

In order for chromatin remodeling to occur, the nucleosomes must be moved with enough time so that the promoter can be bound.  However, moving nucleosomes require energy.  Understanding the rate of transcription and the mechanisms one can predict nucleosome movement.  In addition, transcription can also help predict the chromatin-remodeling rate or genes and genes during development.