CAS BI 216 Lecture Notes - Lecture 8: Long Non-Coding Rna, Constitutive Heterochromatin, Chromosomal Translocation
19 May 2017
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Document Summary
Chromatin end to end - dna = 6 ft: dna is wound around proteins chromosome structure relies on histone and non-histone proteins, 1/3 dna, 1/3 proteins, 1/3 non histone. Protein remain after dna is removed -> chromosome scaffold : non-histone chromosomal proteins. Nucleosome - 167 bases wrapped around 4 histone proteins: histones - are small proteins; highly basic -> bind to dna well. H1 + h2-h4 (core histone proteins) linker - linker dna links to next nucleosome: electron microscopy -> see beads on a string of dna, 100 a, string is abou 20 a. Supercoiling - nucleosomes get coiled again into 300 nm fiber -> higher levels of compaction. Radial look scaffoled - (loops - daisy chains) - mostly speculative: creates the solinoid structure, removing proteins in interphase -> show loops of dna included proteins called condensins -> condense into chromosomes.
