Physiology 3140A Lecture Notes - Lecture 29: Cellular Differentiation, Homeobox Protein Nanog, Epigenome
28 Dec 2017
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Document Summary
Heritable changes in gene expression that do not involve changes in dna sequence but modifications in the chromatin. Dna methylation: generally at cytosines, usually associated with gene repression. There are different mechanisms for how dna methylation works to drive repression. Recruitment of factors that allow for inheritance of histone modifications: target of epigenetic readers, binding sites. Include interacting with histone modifying enzymes or preventing binding of transcription factors: cannot look at an individual modification must look all the other epigenetic modifications that occur too. Involved in inactivation of the x chromosome in females. Imprinting: monoallelic gene expression of maternal or paternal genes: same idea as x inactivation but on a gene-gene or locus-locus basis. Repression of dna translocation: prevents dna translocation, retrotransposon elements: evolutionary inserted into the genome - where genes jump from one area of the genome to another if it is not protected against. Dna can be modified by methylation of cytosines.
