Histone modifications

There are many types of histone modifications, including acetylation, methylation, ubiquitination, citrullination and phosphorylation of specific amino acids within the histone protein, usually towards the C-terminal (‘tail’) end of the protein. These modifications can both positively and negatively regulate gene expression by changing the way in which histones bind to DNA (20).

Histone modifications can be detected using a variety of techniques including mass spectrometry and genomics approaches such as ChIP-chip and ChIP-seq. The genomics approaches combine chromatin immunoprecipitation (ChIP) of specific, modified histones and their associated DNA with microarray (chip) or NGS (seq) of the DNA molecules to identify regions of the genome associated with these modifications (20) (Figure 15).

Figure 15 Immunoprecipitation methods combined with microarrays or next generation sequencing can be used to detect histone modifications.