BIOL308 Study Guide - Final Guide: Corepressor, Repressor, Euchromatin
11 Jan 2015
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Document Summary
Describe the role of histone acetylation/deacetylation in regulation of transcription. Histone acetylation allows for dna to be remodelled so that transcription factors and activators can reach genetic elements and initiate transcription. This occurs because acetylation provides a negative charge to the histones, allowing them to dissociate from dna more freely, which also has a negative charge. The nucleosomes are still intact but can be repositioned to expose promoter elements. Deacetylation allows for transcription to be inhibited, as transcriptional machinery is not able to access the promoter which is held up in tightly wound nucleosomes: describe the role of chromatin remodelling complexes in regulation of transcription. Chromatin remodelling complexes reposition the nucleosomes and can expose promoter elements for binding of gtfs. (atp is used in this process: describe an influence of activators and repressors on assembly of initiation complexes. Activators and repressors can help in recruiting coactivator or corepressor complexes that have histone acetylase or deacetylase activity.
