Epigenetics Flashcards
What does the epigenome aid understanding of?
How a genotype can give rise to a phenotype
How traits can be inherited across generations without alterations in DNA sequence.
How structural adaptation of the genome facilitates activation or repression.
Most modifications are REVERSIBLE.
What are the three main types of chromatin modifications?
Post-translational histone modification (terminal covalent)
DNA methylation (terminal covalent)
Nucleosome positioning
What makes up a solenoid?
5 nucleosomes bind together ina solenoid form.
Describe the amino acid content of the core histones?
What is; H3K9me1
H3K9me3?
More than one fifth of aas = lysine or arginine.
Histone 3, lysine 9, 1 methyl gp = gene activation.
Trimethyl = repression.
What is a CpG island?
Short stretch of DNA in which the frequency of the CG sequence is higher than other regions.
What is Decitabine and how can its use be optimised?
Demethylating drug which reverses CpG methylation in Myelo-Dysplastic syndrome.
Main effect associated with incorporation into DNA.
Low dose and prolonged exposure.
What is EZH2 and how is it targeted in cancer?
Enhancer of Zeste Homolog 2 - histone methyltransferase - methylating H3K27.
- Increase in H3K27me3 in lymphomas - GSK126 (an inhibitor) used.
What else can DNA methylation marker be used for?
Predict response to chemo.
Promoter hypermethylation of MGMT predicts response of glioma to alkylating agents.
