Histone

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Schematic representation o the assembly o the core histones intae the nucleosome.

In biology, histones are heichly alkaline proteins foond in eukaryotic cell nuclei that package an order the DNA into structural units cried nucleosomes.[1][2] Thay are the chief protein components o chromatin, actin as spuils aroond which DNA winds, an playin a role in gene regulation. Withoot histones, the unwoond DNA in chromosomes would be very lang (a lenth tae width ratio o mair nor 10 million tae 1 in human DNA). For example, each human diploid cell (conteenin 23 pairs o chromosomes) haes aboot 1.8 meters o DNA, but woond on the histones it haes aboot 90 micrometers (0.09 mm) o chromatin, which, when duplicatit an condensed during mitosis, result in about 120 micrometers o chromosomes.[3]

References[eedit | eedit soorce]

  1. Youngson RM (2006). Collins Dictionary of Human Biology. Glasgow: HarperCollins. ISBN 0-00-722134-7. 
  2. Cox M, Nelson DR, Lehninger AL (2005). Lehninger Principles of Biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-4339-6. 
  3. Redon C, Pilch D, Rogakou E, Sedelnikova O, Newrock K, Bonner W (Apr 2002). "Histone H2A variants H2AX and H2AZ". Current Opinion in Genetics & Development. 12 (2): 162–9. doi:10.1016/S0959-437X(02)00282-4. PMID 11893489.