CMMB 413 Lecture Notes - Lecture 14: Embryonic Stem Cell, Genomic Imprinting, Nucleosome
30 Apr 2019
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Heritable changes in gene expression not caused by changes in dna sequence. Zygote is totipotent (can giver rise to any cell type, only one to give rise to pluripotent embryonic stem cells) Gene expressed in brain is decondensed (euchromatin) in nucleus of neuron. Its off in the muscle cell, and is seen as a dot in the periphery in the nucleus. Nuclear periphery is an area that is transcriptionally inert (heterochromatin), so to silence a gene, just put it in the periphery. Histone modification: often times, dna methylation drives histone modification and vice versa. Most commonly studied is x chromosome inactivation and genomic imprinting. Nucleosomes are made up of histones (octamer) Chromosomes are a system to divide dna. N terminal tails are the business ends, the structural end is inside. After translation and incorporation into nucleosomes, enzymes can come and add acetyl and methyl and phosphoryl, and ubiquitin groups to n terminal tails.
