Deciphering the histone code using mass spectrometry

During the past decade, studies surrounding chromatin research have grown exponentially. A major focus of chromatin biology is centered on understanding of how histone modifications alter chromatin structure at the molecular and mechanistic levels. Discoveries are being made at a rapid pace due to the advent of new and innovative techniques. Mass spectrometry has emerged as a powerful tool in the field of histone research due to its speed, sensitivity, and ease of use. This has resulted in the identification of a number of novel histone modification sites. In consequence, new roles in biological processes have been discovered and hypothetical models, such as the ‘histone code’ have been reaffirmed or refined. One significant advantage to using mass spectrometric techniques is that the combinations of modifications on different sites can be determined which is crucial to deciphering the ‘histone code’. In this manuscript, the mass spectrometric approaches developed over the past decade for both qualitative and quantitative analysis of histone post-translational modifications (PTMs) are discussed.