Epigenetics

Question 1

basic principle of epigenetics

Answer 1

not all genes are active or expressed at the same time, there are modifications that switch them on/off

Question 2

process wherein a cytosine base has a ch3 or methyl group added to it

Answer 2

methylation on nucleotides

• happens only on cytosines preceding guanines (cpg islands)
• high methylation = gene is not made into rna

Question 3

changes in the configuration of histones

Answer 3

• addition of groups
• regulate proteins made in cells
• loose chromatin = can be expressed
• tightly packed = cannot be read

Question 4

closed chromatin structure

Answer 4

• methylation of lysine 9: silencing of euchromatin or densely packed pericentromeric heterochromatin
• methylation of lysine 27: silencing of key differentiation factors in embryonic stem cells

Question 5

open chromatin structure

Answer 5

acetylation, phosphorylation, methylation

Question 6

t/f maternal diet in pregnancy has no effect on the offspring

Answer 6

false, has an effect. agouti gene!!

Question 7

__ are key components in methionine synthesis

Answer 7

folic acid, b vitamins, s acetyl methionine

- can alter gene expression

Question 8

drugs that can affect gene expression

Answer 8

• bisphenol a (bpa) = turn genes off

- heavy metals (cadmium, nickel, lead) can turn genes on -> risk for cancer

Question 9

epigenetics in cancer

Answer 9

tumor suppressor genes and oncogenes

Question 10

treatment for epigenetic profiles in cancer cells

Answer 10

• azacitadine, decitabine: reverse dna methylation

- vorinostat: histone deacetylase inhibitor

Question 11

dna hypomethylation in sle

Answer 11

• apoptotic dna is able to induce anti-dsdna antibody and sle-like autoimmune disease
• hypomethylation of innate and adaptive immune system = excessive proinflammatory activity

Question 12

histone modification in sle

Answer 12

• downregulation of h3 and h4 acetylation in cd4 t cells

- treatment: hdac inhibitors for splenomegaly and gn

Question 13

methylation in asthma

Answer 13

• promoter agr 1 and arg 2 = no production
• promoter of alox12 = bronchospasm
• treg cells and foxp3
• pcdh-20
• reduced at il13 = aggravation of bronchial inflammation and overexpression of ige

Question 14

triggers for asthma

Answer 14

polluted air and environmental tobacco smoke

Question 15

histone modification in asthma

Answer 15

• higher h4 acetylation = reduced hdac = overexpression of inflammation-associated genes
• glucocorticoids = regulate histone acetylation
• tgf-b2 can inhibit adam33