Histone

Histones are proteins found in eukaryotic cell nuclei, which package the DNA into structural units called nucleosomes.^[1][2] They are the chief protein components of chromatin, the active component of chromosomes.

Histones act as spools around which DNA winds, and play a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long. For example, each human cell has about 1.8 meters of DNA, but wound on the histones it has about 90 millimeters of chromatin, which, when duplicated and condensed during mitosis, result in about 120 micrometers of chromosomes.^[3]

1. ↑ Youngson, Robert M. (2006). Collins dictionary of human biology. Glasgow: HarperCollins. ISBN 0-00-722134-7.
2. ↑ Cox, Michael; Nelson, David R.; Lehninger, Albert L (2005). Lehninger principles of biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-4339-6.{{cite book}}: CS1 maint: multiple names: authors list (link)
3. ↑ Redon C, Pilch D, Rogakou E, Sedelnikova O, Newrock K, Bonner W (April 2002). "Histone H2A variants H2AX and H2AZ". Curr. Opin. Genet. Dev. 12 (2): 162–9. doi:10.1016/S0959-437X(02)00282-4. PMID 11893489.{{cite journal}}: CS1 maint: multiple names: authors list (link)