Biology And Biomedical Sciences BIOL 2960 Midterm: Exam 3 Study Guide

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Activators make chromatin accessible/ & or promote formation of marked site. Promoters are protein-dna complexes embedded in a chromatin environment. Lysine can be modified in tails by acetylation, which neutralizes the charge. Protein core of 8 histones surrounded by dna. Dna is acidic due to (-) charged due to phosphates. Histones are basic due to (+) charged lysine and arginine. Writers: covalent modification of histone aa (methyl/acetyl transferase) hat. Erasers: restore modified histone aa to unmodified form (demethylases/acetylates) Core promoter (tata box): required to recruit gtfs and rna pol to non-chromatin dna. General transcription factors (gtfs): required for basal transcription in vitro. Assemble with rna to form pre-initiation complex (pic) Dna is not yet opened to expose template strand for transcription. Activation: dna melting catalyzed by tfiih, phosphorylation of ctd of rna pol ii by a tfiih kinase. Mediator (med) = rna pol ii associated complex. Not required for basal transcription in vitro, but also is a gtf.