CEM 311 Lecture Notes - Lecture 43: Histone H1, Histone Fold, Rna Splicing
Document Summary
H1 induces tighter wrapping around nucleosome, organizing 10nm fiber into 30nm fiber. 30nm fiber contains dna, core histones and h1. Two types of models for the 30nm chromatis structure different on the length of linker. Exons are the protein coding sequences (about 2% of the genome in humans). Introns are non-coding dna, some are involved in gene regulation but most with unknown functions. Introns are removed from rna by rna splicing. (primary rna transcript remove introns spliced mrna) Creates a complex of the four different histone protein (2 of each): h2a, h2b, h3, h4 (h1 as a linker histone). Lysine and arginine rich, making them basic help with binding with the acidic dna. The common histone fold consists of three helices. The assembly of a nucleosome is initiated by the formation of h3. h4 tetramer, as it binds to dsdna. The dna-h3. h4 will then recruit two copies of the h2a. h2b dimer. H1 histone is a basic protein like the other histones.
