One of the main building blocks of chromatin – the histone proteins, are subject to wide array of post-translational modifications. A major role of these marks is to recruit various protein factors which can bring about specific functional effects. In a close collaboration with the Guest Research Group Chromatin Biochemistry (Wolfgang Fischle) we aim at defining the complement of factors that is necessary and sufficient to translate single and patterns of chromatin marks into function. In a first step, we are using recombinant, defined chromatin templates to ‘fish’ for such factors using a pulldown strategy from cellular extracts in combination with quantitative mass spectrometry (SILAC). In a second step we are using bioinformatics approaches to systemically isolate chromatin interaction networks and to narrow down the list of chromatin factors essentially defining a chromatin domain.