CATCH-IT method for measuring nucleosome turnover. Drosophila melanogaster

Direct measurement of nucleosome turnover dynamics by using co-translational incorporation of the methionine (Met) surrogate azidohomoalaine (Aha) into proteins and subsequent ligation of biotin to Aha-containing proteins through the [3+2] cycloaddition reaction between the azide group of Aha and an alkyne linked to biotin. To measure turnover rates, we treat cells briefly with Aha, couple biotin to nucleosomes containing newly incorporated histones, affinity purify with strepavidin, wash stringently to remove non-histone proteins and H2A/H2B dimers, and analyze the affinity-purified DNA using tiling microarrays. We call this strategy 'CATCH-IT' for Covalent Attachment of Tags to Capture Histones and Identify Turnover. Keywords: Chromatin affinity-purification on microarray Overall design: All experiments were done using strepavidin pulldown DNA cohybridized with total input DNA to the same array. Two channels per array, Cy5 and Cy3, were used in each experiment.