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Flashcards in Epigenetics Deck (12):

Describe acetylation

Gene expression, euchromatin, open structure
Acetyl transferase
Histone deacetylases
+ve charged lysine has acetyl group added- neutralises charge
Less affinity for -vely charged DNA - weakens interactions


Histone methylation

Gene silenced
Histone methyltransferase
Histone demethylase (KMT2A)
+ charges aa has methyl group added which increases + charge
Increases affinity for DNA- binds tighter


Name 4 epigenetic mechanisms

DNA methylation
Histone modification
Short non coding RNA
Long non coding RNA


Describe micro RNA mechanism

Interferes with expression at translation
Regulates translation of mRNA to aa
Degrades mRNA - binds 3'UTR mRNA and induces enzymatic degradation
MRNA specific


Describe lncRNA mechanism

Interacts with chromatin
Regulates Histone modification- hetero- to EU- chromatin & vice versa
Cell type specific
Respond to environmental stimuli


Name two results of hypermethylation in cancer

Silences TSG
causes microsatellite instability


Name results of hypomethylation in cancers

Increase genomic instability
Re activation of transposable elements
Loss of imprinting
Favours chromosome instability/ rearrangements


Name two cancers associated with hypomethylation and loss of imprinting

Wilms tumour
CRC/ lung/liver: loss control of IGFR causes increases of expression


Name two types of epigenetic therapy

Targeting DNA methylation
Targeting Histone modification


Describe DNA methylation based epigenetic therapy and an example of disease/drug

Acts like cytosine- incorporates into DNA at replication and inhibits DNMT enzymes from acting (methylating)
Re activates silenced gene
MDS: 5-azacytidine. / 5-aza-3'-deoxycytidine


Describe Histone modification based epigenetic therapy and disease its associated with

Histone deacetylase inhibitors
Prevent removal of acetyl group from lysine- prevents gene from being silenced
Neurological/ neurodegenerative disease


Describe DNA methylation

Gene silencing
DNA methyl transferase DNMT
Methyl group added to 5'cytosine in CpG Island
Physically inhibits binding of transcription factors
Attracts MBD methyl CpG domain binding proteins (MeCP2) they attract his tone deactylases