BIOLOGY 3UU3 Lecture Notes - Histone Deacetylase, Histone H3, Histone Code
9 Feb 2013
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Document Summary
Control the structure and expression of large chromosome domains. Has many rounds of of histone modification through silencing complexes that spread along the chromatin fibre by self-oligomerization and association with modified histone amino-terminal tails. Folding of dna in chromatin regulate processes such as gene expression and chromosome dynamics. Local chromatin regulation is at a single gene, on the globla scale its at chromosome domains or the entire chromosome can both at the nucleosome (the fundamental unit of chromosome folding) Chromosomes have 2 types of domains: euchromatin, heterochromatin - Heterochromatin domains: inaccessible by dna binding factors and are transcriptionally silent. Euchromatin domains: accessible by dna binding factors, and are transcriptionally active. Large heterochromatin surrounds functional chromosome structures like centromeres and telomeres. Small heterochromatin structures are found throughout the chromosome. Heterochromatin plays a central role in centromere function. Heterochromatin proteins are associated with dna repeats that surround centromeres. Heterochromatin also stabilizes repetitive dna sequences at centromeres, telomeres, and elsewhere in the genome.
