Physiology 3140A Lecture Notes - Lecture 5: Cpg Site, Dna Methyltransferase, Dna Replication
3 Jul 2017
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Lecture 5 pin is such a lil bitch. Shit from previous lecture that is additional bullshit that you have to know that triggers me so hard because keeners. Individual methylation and demethylation occur focus more on trimethylation: h3k4me1 transcriptional silencing (restricts recruitment of enzymes to certain regions within promoter, h3k4me2 marks enhancers where transcription factors bind (enhances) Dna methylation: recall: usually at cytosines, ex. Primary human fibroblast cell line demonstrates 4. 25% of total cytosines in genome are methylated: 2/3 of all cpg sites are methylated with 99% of all methylation occurring in cpg dinucleotides. Cpg islands: these have 10-fold higher frequency of the cpg dinucleotide than rest of genome. In a 200bp sequence with a c+g content of 50% (average) the observed cpg/expected cpg is > 0. 6. At cpg islands outside the promoter there would be much more: hypermethylated promoters are found in cancer. Dna methylation promoting enzymes: 2 classes: dmnt3a and dmnt3b (known as de novo.
