Epigenetics: Regulation of gene activity by histone modifications

In all cells of our bodies DNA is found complexed with basic proteins, the so-called histones. These proteins not only organize and protect the genetic information, but are also crucially involved in all biological processes involving DNA. In this aspect, a large number of different post-translational histone modifications direct the availability and accessibility of the DNA. While many histone modifications could be linked to different biological phenomena and signal transduction pathways, the molecular working mechanisms of most histone modifications are still not understood.