The biological functions of given genomic regions are ruled by the local chromatin composition. The Proteomics of Isolated Chromatin segments approach (PICh) is a powerful and unbiased method to analyze the composition of chosen chromatin segments, provided they are abundant (repeated) or that the organism studied has a small genome. PICh can be used to identify novel and unexpected regulatory factors, or when combined with quantitative mass spectrometric approaches, to characterize the function of a defined factor at the chosen locus, by quantifying composition changes at the locus upon removal/addition of that factor.
Keywords: Chromatin; Heterochromatin; Protein Purification; Proteomics; Repeated Sequences; Telomeres.