Test 1 - Neuroepigenetics

Question 1

When we say nature vs. nurture to what do nature and nurture refer?

Answer 1

Nature refers to genetics and nurture refers to environment

Question 2

Are innate behaviors completely controlled by genetics?

Answer 2

No, innate behaviors are not 100% controlled by genes. Innate behaviors also called instincts can be altered in lab settings and then passed down to offspring such as the mice & ferret urine study.

Question 3

What is neural plasticity?

Answer 3

Axons and dendrites (processes) can grow towards each other or shrink away from each other

• changing of neural networks
• environment has effect on nerve communication

Question 4

What is the difference between monozygotic and dizygotic twins and which kinds of studies would you use each for?

Answer 4

Monozygotic: 2 embryos from same egg that splits - identical - epigenetics studies

Dizygotic: 2 separate eggs fertilized from 2 different sperm - fraternal - genetics studies

Question 5

In studies with monozygotic twins that were separated at birth - can you 100% say that any differences are due to epigenetic changes?

Answer 5

No, you can not say that 100% because of mutagens.

Question 6

Define epigentics.

Answer 6

Changs in phenotype without change in genotype found in the histones & DNA methylation (chemical marks on DNA)

Question 7

What enzyme does DNA methylation?

Answer 7

DNMTS - DNA Methyl transferases (transfer methyl groups to DNA)

Question 8

What happens when there is too much DNA methylation?

Answer 8

Too much DNA methylation is typically associated with gene silencing, since protein transcription is blocked

Question 9

What enzyme type adds a hydroxyl group to methylated cytosines

Answer 9

TET enzymes (10-11 translocase)

Question 10

What is the eventual result of hydroxymethylated DNA and what is its effect on gene expression?

Answer 10

TETs induce hydroxy methylation which is a conversion of methylated DNA back to unmethylated resulting in an increase in gene expression

Question 11

What is a histone?

Answer 11

Protein in the nucleus that DNA wraps around (how we can have so much DNA in a small are)

Question 12

What are the two possible modifications of histones?

Answer 12

1. location of the modification
2. how many methyl groups added

Question 13

What enzyme types do the modifications to histones?

Answer 13

1. HMTs (histone methyl transferases): methylation and demethylation
2. HATs (histone acetyl transferases) & HDACs (histone deacetylase): acetylation and deacetylation

Question 14

When histones are acetylated, what effect does this have on gene expression?

Answer 14

Acetylated histones have an increase in gene expression because they are wrapped less tightly

Question 15

When histones are methylated, what effect does this have on gene expression?

Answer 15

Methylated histones have a decrease in gene expression because they block transcription from occurring.

Question 16

What does it mean that an RNA is non-coding?

Answer 16

Non-coding is an RNA that is not going to be translated into a protein

Question 17

Explain how miRNA regulates expression of a gene.

Answer 17

When miRNA binds to a portion of mRNA it signals RISC to bind and degrade the mRNA. This removes the mRNA and its protein cannot be transcribed resulting in a decrease of gene expression.

Question 18

What are possible environmental factors that influence epigenetic marks?

Answer 18

1. diet (folic acid; B12)
2. chemicals (BPA; drugs)
3. abuse; neglect
4. maternal immune response (flu during pregnancy, etc.)

Question 19

What can you say about epigenetic marks between regions of the brain?

Answer 19

Epigenetics most likely influences or causes different brain regions (neural plasticity) - There are increased levels of DNA methylation/hydroxymethylation between brain regions

Question 20

Neuroethology

Answer 20

study of animal behavior in the natural environment

Question 21

What is a big factor in neural plasticity and it efficacy?

Answer 21

age - after 26 new neurons can not regenerate

Question 22

What were the 3 examples discused about neural plasticity and innate behaviors?

Answer 22

1. ferret urine with rats
2. chick hawk vs goose
3. owls with prisms

Question 23

Mutagen

Answer 23

something that changes the DNA sequence (changes actual DNA)

Question 24

Heritability

Answer 24

the difference between monozygotic and dizygotic twins (how well does the trait correlate between them

Question 25

MECP2

Answer 25

protein that likes to bind to methylated cytosines of DNA - MECP2 binds to methylated and just sits there which blocks the transcription factor proteins from reaching the promoter

Question 26

What are the 4 types of histones?

Answer 26

1. H2B
2. H2A
3. H4
4. H3

Question 27

What is the amino acid that generally receives modifications?

Answer 27

K - lyseine

Question 28

Chromatin state

Answer 28

how tightly DNA is wrapped around histones

Question 29

How to name histone mods - H3K4me1

Answer 29

H3 = histone type
K = amino acid location
4 = residue (location of a.a.)
me = type of mod (me vs. ac)
1 = # of mods (ac always blank)

acetylation always active

Question 30

RISC

Answer 30

RNA induced silencing complex - binds to miRNA bound to UTRs and degrades the mRNA

Question 31

miRNA-132

Answer 31

when it is decreased - HDAC1 & DNMT3A increase - and gene expression decreases - found in schizophrenia and autism development