Lecture 12. Eukaryotic Transcription

Question 1

Where does bacterial transcription and translation?

Answer 1

In the same compartment

Question 2

Where are eukaryotic transcripts transported to?

Answer 2

Cytosol

Question 3

Where are the mRNA precursors processed?

Answer 3

In the nucleus

Question 4

What does eukaryotic RNA polymerase require?

Answer 4

General transcription factors

Question 5

Conserved elements of eukaryotic RNA Polymerase II promoters

Answer 5

Inr
TATA box
DPE
Enhancer

Question 6

Inr

Answer 6

Initiator element

Question 7

TATA box promoter

Answer 7

Contains a TATA box: The upstream sequence TATAAAA usually between -30 and -100 from transcriptional start

Question 8

TATA-less promoter

Answer 8

Downstream core promoter element between +28 and +32 from transcriptional start

Question 9

Enhancer

Answer 9

Can be several kb away

Question 10

Similarities between bacterial and eukaryotic replication mechanisms

Answer 10

NONE - fundamentally different RNA replication mechanisms

Question 11

What guides RNA Pol II to its promoters?

Answer 11

TFIID

Question 12

What does bound TBP act as in initiation?

Answer 12

A nucleus for further recruitment

Question 13

What is TFIIH?

Answer 13

A helicase that opens the DNA double helix and a kinase that phosphorylates the C’ - terminal domain of the RNA Pol II L’ subunit

Question 14

Elongation process

Answer 14

1. TFIIB, E and H dissociate from the basal transcription apparatus
2. RNA is synthesised
3. RNA Pol II progresses, freeing the promoter and TFIID/A complex for further recruitment

Question 15

What is a potent inhibitor of RNA polymerase II

Answer 15

α-amanitin

Question 16

What do enhancers do?

Answer 16

They increase the transcriptional levels of ges

Question 17

The DNA looping model

Answer 17

Proteins bound to a distant enhance interact with components of the transcription initiation complex, thus looping out the intervening DNA

Question 18

What does the mediator protein do in the DNA looping model?

Answer 18

Act as a bridge between activator proteins that bind the enhancer control elements and the non-phosphorylated CTD of RNA Pol II in its initiator state

Question 19

In what three ways are the RNA Pol II transcripts (mRNAs) modified?

Answer 19

1. The 5’ end is capped by a nucleotide triphosphate through an unusual linkage. The process is accompanied by methylation
2. The 3’ end of the primary transcript is trimmed and a poly-A tail is added
3. Introns are removed by splicing