Did you mean deacetylation as acetylation makes it possible to transcribe and not gene silencing.

Allows for DNA binding proteins to interact with sites to activate gene transcription and alters the accessibility of chromatin.

See for example "Lysine Acetylation Targets Protein Complexes and Co-Regulates Major Cellular Functions" by Chunaram Choudhary, Chanchal Kumar, Florian Gnad, Michael L. Nielsen, Michael Rehman, Tobias C. Walther, Jesper V. Olsen, Matthias Mann, Science, 14 Aug 2009, which demonstrates that "the regulatory scope of lysine acetylation is broad and comparable with that of other major posttranslational modifications".