Gene Expression

Question 1

What regulates gene expression?

Answer 1

proteins (transcriptions factors and co regulators) and miRNA

Question 2

what is differential mRNA splicing and its significance?

Answer 2

splicing of introns from primary mRNA can occur in many different ways thus mRNA splicing yields in a transcriptome that is much larger than the number of genes in our genome

Question 3

what is a core promotor?

Answer 3

minimum DNA sequence required for transcription initiation

Question 4

what are enhancers?

Answer 4

DNA elements that stimulate transcription from a distance

Question 5

What are silencers?

Answer 5

DNA elements that repress transcription from a distance

Question 6

What are transcription factors?

Answer 6

proteins that help polyII bind to core promotor and initiate transcription at specific times in specific cell types

Question 7

Fun facts about transcriptions factors

Answer 7

• main regulators of gene expression and are aided by co factors to modulate transcriptional activity
• bind to promotor or enhancer
• activate or inhibit gene expression
• multiple transcription factors can act in combination

Question 8

What is a enhancesome ?

Answer 8

multiple enhancers that act in combination on common promotor

Question 9

What is a CpG island?

Answer 9

proximal promotor elements binding transcription factors like Sp1 to promote initiation of transcription

Question 10

Hormone receptor, ER, GR, and PR are examples of what?

Answer 10

transcription factors

Question 11

What are miRNA’s?

Answer 11

short regulatory RNA complementary to other mrNA usually at 3’UTR

Question 12

What do miRNA’s do?

Answer 12

decrease expression of complimentary mRNA by inhibiting translation or causing degradation of RNA

Question 13

What are the 2 ways miRNA regulate gene expression?

Answer 13

repress translation

cleave mRNA

Question 14

What important proteins are involved with the mechanism of miRNA’s?

Answer 14

Drosha & Dicer

Question 15

How does miRNA control gene expression at the transcriptional level?

Answer 15

binding to promotor region of DNA

Question 16

What is epigenetics?

Answer 16

heritable changes that are not the result of change of DNA sequence?

Question 17

What are the mechanisms of epigenetic inheritance?

Answer 17

DNA methylation
histone modification
regulatory non-coding RNA’s (miRNA)

Question 18

Why is chromatin important?

Answer 18

plays a important role in the regulation of transcription. Gene has to be accessible for it to be transcribed

Question 19

What are histones?

Answer 19

primary regulatory elements for chromatin structure and gene expression AKA (histones regulate DNA packaging)

Question 20

What are three ways you can regulate histones?

Answer 20

acetylation, methylation, and phosphorylation

Question 21

What two enzymes are involved in histone acetylation?

Answer 21

HAT & and HDAC

Question 22

What happens in histone acetylation?

Answer 22

1. • charge from amino acid removed
2. changes chromatin from a closed state to a open state for transcription.
3. increase in gene expression

Question 23

HDAC’s or histone deacetylases do what?

Answer 23

decrease gene expression

Question 24

What are sirtuins?

Answer 24

NAD+ dependent HDAC’s

Question 25

where does DNA methylation occur?

Answer 25

exclusively CpG sites in human cells

Question 26

What does DNA methylation do?

Answer 26

it suppresses gene transcription ( removes TF from the CpG promotor region)

Question 27

What can contribute to cancer susceptibility?

Answer 27

hyper and hypo methylation

Question 28

Can epigenetic changes be revised?

Answer 28

YES unlike mutation

Question 29

What is Vorinostat and what does it do?

Answer 29

its a histone deacetylase inhibitor (increases gene expression)
used for cell lymphoma