Epigenetics

Histones

The study of chromatin associated proteins, such as histones, their assembly with and modification by enzymatic regulators is an important area of epigenetic research.

Chromatin is organized into nucleosome core particles that consist of approximately 147 bp of DNA and an octamer complex made up of two molecules of each histone (H2A (NEB M2502), H2B (NEB M2505), H3 (NEB #M2503, NEB M2506, NEB M2507) and H4 (NEB M2504)). The linker histone, H1 (NEB M2501), can further condense chromatin by binding to linker DNA between the nucleosome core particles. For histone modification studies, New England Biolabs offers a selection of unmodified, recombinant human histones and the EpiMark® Nucleosome Assembly Kit (NEB #E5350) which contains preformed Histone H2A/H2B Dimer (NEB M2508) and Histone H3.1/H4 Tetramer (NEB M2509).

NEB's highly purified, recombinant histones are excellent substrates for the characterization of histone modification enzymes. Mass spectrometry analysis demonstrates that they are free of post-translational modifications. In addition, assembly of recombinant nucleosomes has been greatly simplified by the introduction of the EpiMark® Nucleosome Assembly Kit (NEB #E5350)

EpiMark® is a registered trademark of New England Biolabs, Inc.

Videos

  1. What Is Epigenetics?

    If all cells are created from the same genetic material, why are there so many different cell types? Listen to Sriharsa Pradhan, Senior Scientist, RNA Biology at NEB, as he describes how DNA is methylated and how this affects the path of reading the DNA code the same way an obstruction would derail a train off its tracks.

Types of Histone Modifications

Amino Acid Modification
Lysine Methylation, Acetylation,
Ubiquitination, Sumoylation,
ADP-Ribosylation
Arginine Methylation
Serine Phosphorylation
Threonine Phosphorylation

Gel Shift Assay to Visualize Nucleosome Assembly

Samples from nucleosome assembly reactions were run on 6% polyacrylamide gel in 0.5X TBE. Lane 1: Low Molecular Weight DNA Ladder (NEB #N3233)
Lane 2: Nucleosome Control DNA
Lane 3: 0.5:1 ratio of Octamer* to DNA
Lane 4: 1:1 ratio of Octamer* to DNA

*Octamer = 2:1 mix of Histone H2A/H2B Dimer and Histone H3.1/H4 Tetramer.

SDS-PAGE Analysis of the Histones Available from NEB

1: Histone H1° (NEB #M2501) 1 μg
2: Histone H2A (NEB #M2502) 1 μg
3: Histone H2B (NEB #M2505) 1 μg
4: Histone H3.1 (NEB #M2503) 1 μg
5: Histone H3.2 (NEB #M2506) 1 μg
6: Histone H3.3 (NEB #M2507) 1 μg
7: Histone H4 (NEB #M2504) 1 μg
8: Histone H2A/H2B Dimer (NEB #M2508) 2 μg
9: Histone H3.1/H4 Tetramer (NEB #M2509) 2 μg
10: NEB Protein Ladder (NEB #P7703)