Histone Code

Question 1

Memory

Answer 1

cells can accrue changes in transcription (epigenetic) in response to neuron activity - helps consolidate long–term memory

Question 2

Transgenerational memory

Answer 2

Stree can induce changes at the level of epigenetics that are inhereted (when women go through a lot of stress at a certain point of their pregnancy their kids sometimes are born with birth defects)

Question 3

Vernalization

Answer 3

Examples in plants showing an epigenetic ‘memory’ of winter seasons, adjusts developmental timing in response to the seasons

Question 4

MEF2

Answer 4

Involved with muscle fate

Question 5

Histone tail

Answer 5

N-terminal segments of histones protrude from the nucleosome, reversible modifications of histone tails regulate chromatin dynamics and DNA accessibility

Question 6

histone code hypothesis

Answer 6

chemical changes to histone proteins modify DNA transcription

Question 7

Post transitional modifications

Answer 7

chemical changes to histone proteins that modify DNA transcription only happen following the translation of mRNA coding for histone proteins

Question 8

post translational modifications

Answer 8

modifications made to mRNA formed by transcription of DNA to mRNA, 5’ methyl cap on the mRNA, 3’ poly A tail, splicing of mRNA transcript

Question 9

Naming conventions for histone modifications

Answer 9

Indicate histone, amino acid/position, type of modification

Question 9

Naming conventions examples Histone H3 acetylated at lysine (K) 27

Answer 9

H3K27ac

Question 10

lysines methylation and naming

Answer 10

Lysines can be monomethylated (me1, dimethylated (me2), and trimethylated (me3),

Question 11

methylation naming example: Histone H3 trimethylated at lysine (K) 27

Answer 11

H3K27me3

Question 12

writer proteins

Answer 12

Lysine (K) acetyltransferases (KATs) add acetyl groups to histones

Question 13

Readers

Answer 13

Bromo domains, proteins with bromodomains bind acetylated lysines

Question 14

Erasers

Answer 14

KDMs, Histone/lysine (K) deacetylases remove acetyl groups

Question 15

H3K4me3

Answer 15

(readers) transcriptional activation (thithorax group proteins)

Question 16

H3K27me3

Answer 16

(readers) transcriptional repression (polycomb group proteins)

Question 17

Polycomb

Answer 17

discovered in fruitflies, regulate HOX genes (repress) through epigenetic modification of chromatin structure , transformed posterior legs to anterior legs which have comb like bristles

Question 18

Trithorax

Answer 18

participate in activation of gene transcription in early development

Question 19

PRC2

Answer 19

H3K27me3 writer

Question 20

PRC1

Answer 20

H3K27me3 reader

Question 21

PRC1, PRC2

Answer 21

together they stably repress gene expression

Question 22

Nucleosomes in the presence of polycomb complex proteins

Answer 22

are compacted

Question 23

Histone marks spreading

Answer 23

some readers of histone marks are able to recruit writers that propagate the , resulting in lateral spread of active or inactive states along chromatin fibres, some DNA sequences act as barriers (insulators) and stop the spread of chromatin marks

Question 24

How is the activity of an enhancer targeted to specific genes

Answer 24

CTCF proteins bind each other and create stable chromosome loops that act as chromosomal neighbourhoods and act as epigenetic Insulators (prevents propagation of post translational modification)

Question 25

CTCF Gene

Answer 25

so called because it binds to a certain consensus sequence (CCCTC binding factor), acts as an insular protein

Question 26

Insulator protein

Answer 26

Defines the boundaries between different genomic regions, controls transcriptional units within the genomic