Quantification of histone modifications using 15N metabolic labeling

Mass spectrometry has made major contributions to recent discoveries in the field of epigenetics, particularly in the characterization of the myriad post-translational modifications (PTMs) of histones which are technically challenging to analyze. These new developments have further aroused great interest in development of robust, new mass spectrometric methods to quantitatively study the dynamics of histone modifications. This review covers quantitative analysis of histone PTMs and discuss an 15N metabolic labeling procedure for quantifying histone PTMs applied to the analysis of methyltransferase knockouts in the model organism, Tetrahymena thermophila.