Lecture 24 W11 - Lecture 24 (3-14-11) Notes I. DNA...

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Lecture 24 (3-14-11) Notes I. DNA methylation A. Methylation of cytosines of DNA can result in long-term silencing of gene expression 1. The modification is stable even after many cell divisions B. Roles of DNA methylation 1. required for keeping some genes permanently off after cell differentiation. 2. It is also involved in X chromosome inactivation, where one X in a female mammalian cell is highly condensed and silenced. 3. Genomic imprinting – where one allele of a gene from the sperm or egg is methylated. C. DNA methylation is catalyzed by DNA methlytransferases, that are recruited to specific regions by regulatory transcription factors. 1. Hit and run mechanism – after the initial recruitment, the modification is stably inherited after each cell division D. Piggy back model of maintaining DNA methylation patterns – after DNA replication, the hemi-methylated DNA is automatically converted to fully methylated DNA. II. Epigenetics
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Lecture 24 W11 - Lecture 24 (3-14-11) Notes I. DNA...

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