MBIO 3410 Lecture Notes - Lecture 5: Microsoft Small Basic, Histone H2B, Histone H2A
24 Dec 2015
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Document Summary
Smallest protected unit of dna 146 bp. Small basic proteins with overall positive charge. Other histones exist that are modifications of the above histones. 146 pb of dna wrapped around histone (two twists of dna: core histone 2 each of h2a, h2b, h3, h4, forms 10 nm fiber. 30 nm fiber forms loops on matrix or scaffold attachment region. Chromatin dynamic: some regions are very open and some are very compact, open chromatin dnase i sensitivity. Insulators are dna sequences that recruit factors that allow for boundaries to be established between compact and active regions of the chromatin. Acetyl group added to lysines: histone deacetylases (hdacs) Negative for expression: phosphorylation of histones. Positive for expression: methylation of of histones. Methyl group added to lysines and arginines. Negative for expression: ubiquination of histones. Involved in cell cycle progression, signal transduction, transcription, and translational regulation: histone methylation recruits histone deacetylases higher compaction. Atp-dependent chromatin remodeling complexes: moving, removing, or restructuring nucleosomes.
