BIO SCI 97 Lecture 12: Lecture 12 Notes
22 Dec 2018
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Document Summary
Biochemical changes that regulate gene expression without altering dna sequence. Includes dna methylation, histone modification, x chromosome inactivation, etc. They are directly associated with gene transcription. Epigenetics is a way to restrict access to the genome and store identity information. Chromatin remodeling - refers to modifications that reposition nucleosomes carried out. Open/closed chromatin - in part by writers, erasers, and readers. Open chromatin - relaxed association between dna and nucleosomes, and allows for access by regulatory proteins. Closed chromatin - produced by modifications that cause regulatory sites to be covered by nucleosomes, restricting access. Dna methylation - occurs on a c that is followed by a g (cpg) Cpg islands are found near gene promoters. Another way to regulate tissue specific gene expression. Catalyze the transfer of a methyl group to dna. Nucleosomes - physically impede transcription and reduce transcription factors access to. Biochemical characteristic of histones corresponds to the nucleosome dependent chromatin compaction and dna accessibility.
