text: Protein interference is the process where in some signaling protein interacts, either with the promoter or with some stage of the partially constructed complex, to prevent further construction of the polymerase complex, so preventing initiation. In general, this is a very rapid response and is used for fine level, individual gene control and for cascade processes for a group of genes useful under a specific conditions (for example, DNA repair genes or heat shock genes).
  Chromatin structure inhibition is the process wherein the promoter is hidden by chromatin structure. Chromatin structure is controlled by post-translational modification of the histones involved and leads to gross levels of high or low transcription levels. See: chromatin, histone, and nucleosome.
  These methods of control can be combined in a modular method, allowing very high specificity in transcription initiation control.