[5] H4K20me2 is similar to H4K20me1 but has a different distribution and this dimethylation controls the cell cycle and DNA damage response.
[9] The genomic DNA of eukaryotic cells is wrapped around special protein molecules known as histones.
[12] The current understanding and interpretation of histones comes from two large scale projects: ENCODE and the Epigenomic roadmap.
This led to chromatin states which define genomic regions by grouping the interactions of different proteins and/or histone modifications together.
Chromatin states were investigated in Drosophila cells by looking at the binding location of proteins in the genome.
[15] A look in to the data obtained led to the definition of chromatin states based on histone modifications.
This additional level of annotation allows for a deeper understanding of cell specific gene regulation.
[17] H4K20 was one of the earliest modified histone residues to be identified back in pea and calf extracts in 1969.
It results in good optimization and is used in vivo to reveal DNA-protein binding occurring in cells.
ChIP-Seq can be used to identify and quantify various DNA fragments for different histone modifications along a genomic region.
Micrococcal Nuclease sequencing (MNase-seq) is used to investigate regions that are bound by well positioned nucleosomes.