BIOL 2040 Lecture Notes - Lecture 21: Histone Deacetylase, Histone Code, Epigenome
Document Summary
Nucleosomes attached to dna because of ionic interaction. Sw1/snf complex knows where to slide nucleosomes for remodelling. To disrupt the intaction we can remove the positive charge in histone/nucleosome proteins. Histone acetylation (hat enzyme) transcription (reversible; intuitive because we need regulation not all or nothing switch) Histone acetyl transferase (hat): acetylates and recognizes partially acetylated nucleosomes in order to fully acetylate them activation of transcription. Hdac (histone deacetylase complex): removes acetylation to repackage. **recall within the same homogenous organ you have the same epigenome! ** histone acetylation removes the + charge on the protein; causing the release of histone from dna. ** other methods (except acetylation) can also chemically modify the histone. Histone code: a lot of modification possibilities on a single code. Always methylated 5" cg 3" where c"s are methylated! Cg"s are not methylated near the promotor because promotor needs to be transcriptionally active. Cpg islands exist in minimal promotors (repeated cg sequences)
