Eukaryotic Transcription Regulation

Question 1

What is the first stage of the pre initiation complex assembly?

Answer 1

TFIID/TFB binding to the DNA via the TFB sub unit

Question 2

TFIIA function and what it binds to

Answer 2

TFIIA binds to TFIID/TFB

Stabilises TFB in TFIID/TFB complex interaction with DNA

Question 3

TFIIB function and what it binds to

Answer 3

TFIIB binds to TFIID/TBP complex

Facilitates recruitment of Pol II

Question 4

TFIIE function

Answer 4

To recruit TFIIH

Question 5

TFIIH binds to and fucntion

Answer 5

TFIIH binds to TFIIE

1. Opens promoter to load polymerase
2. Phosphorylates CTD on Pol II so capping enzymes can be recruited

Question 6

TFIIF function and when it’s recruited

Answer 6

TFIIF stabilises Pol II interaction with TFIIB and TFIID

Recruited at the same time as Pol II

Question 7

What is the function of TFIIS during elongation in transcription?

Answer 7

When RNA accidentally backtracks, TFIIS stimulates cleavage of RNA at the polymerisation site to produce a new 3’OH that the polymerase can act on

Question 8

Which three temporally distinct stages is transcription in eukaryotes regulated by?

Answer 8

1. initiation
2. elongation
3. termination

Question 9

How does Poll II navigate nucleosomes?

Answer 9

nucleosome/chromatin remodelling enzymes unpack nucleosomes ahead of the polymerase and repack them behind the polymerase

Question 10

Which nucleosome/chromatin remodelling proteins help Poll II to navigate nucleosomes?

Answer 10

FACT
SWI/SNF
PAF

Question 11

How does termination occur? (3)

Answer 11

1. Polymerase transcribes through a polyadenylation signal within the DNA
2. CAP recognises the polyadenylation signal and bins to the polymerase and the signal and then cleaves 10-30bps after PAS. The free end of RNA attached to the polymerase is degraded.
3. CAP complex puts a polyAtail on the other end of free RNA

Question 12

How many protein coding genes does the human genome contain?

Answer 12

20 000

Question 13

What contributes to cell identity and function?

Answer 13

the relative abundance of each of those 20 000 gene products

Question 14

What determines which gene products are made in a cell?

Answer 14

transcription factors (activators or repressors)

Question 15

How many genes encode transcription factors in teh human genome?

Answer 15

1600 genes

Question 16

Main family of TFs that regulation in humans is done by?

Answer 16

C2H2 zinc finger transcription factors (50% of TFs in human genome)

Question 17

What two domains do transcription factors have?

Answer 17

DNA binding domain

protein-protein binding domain

Question 18

Role of TFs initiation?

Answer 18

Recruit pre initiation complex (PIC)

Question 19

General Transcription Factors

Answer 19

General TFs = the pre-initiation complex (NOT the TFs that recruit it)

Question 20

where does the pre initiation complex assemble?

Answer 20

on a core promoter