Difference between revisions of "KSH 0611 Review Epigenetic modifications regulate gene expression"

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imported>Seung-hoon Kim
imported>Seung-hoon Kim
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<h2>Chromatin - Histone protein / DNA complex&nbsp;in eukaryotic cells</h2>
 
<h2>Chromatin - Histone protein / DNA complex&nbsp;in eukaryotic cells</h2>
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<p>Basic Unit - nucleosome - 146 bp of DNA wrapped around an octamer of the four core histones (H2A, H2B, H3 and H4)</p>
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<li>Euchromatin - transcriptionally active state - the region where DNA is accessible due to the relaxed state of nucleosome arrangement</li>
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<li>Heterochromatin - transcriptionally inactive state - the area where DNA is packed into highly condensed forms that are inaccessible to transcription factors</li>
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<li>&nbsp;</li>
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Revision as of 01:43, 11 June 2016

 Epigenetics


Definition : Heritable changes in gene activity and expression that occur without alteration in DNA sequence

Two well-known epigenetic modifications

  1. Chemical modification to the cytosine residues of DNA (DNA methylation)
  2. Histone modification

Why is it important ? >>> Epigenetic  modifications regulate gene activity and expression during development and differentiation, or in response to environmental stimuli

Epigenetics is considered a bridge between genotype and phenotype

Explain how cells carrying identical DNA differentiate into different cell types >>> Epigenetics

Epigenome - global analyses of epigenetic markers across the entire genome

Chromatin - Histone protein / DNA complex in eukaryotic cells

Basic Unit - nucleosome - 146 bp of DNA wrapped around an octamer of the four core histones (H2A, H2B, H3 and H4)

  1. Euchromatin - transcriptionally active state - the region where DNA is accessible due to the relaxed state of nucleosome arrangement
  2. Heterochromatin - transcriptionally inactive state - the area where DNA is packed into highly condensed forms that are inaccessible to transcription factors
  3.