Transcription (exam 2)

Question 1

Gene sequence written as mRNA

Answer 1

sense strand

Question 2

Template strand

Answer 2

antisense strand

Question 3

Prokaryotic initiation steps

Answer 3

1. Polymerase binds promoter
2. Polymerase melts duplex DNA near TSS, forming a transcription bubble
3. Pol catalyzes phosphodiester linkage between original rNTPs
4. Pol advances in 5’ to 3’ direction
5. At stop site, pol dissociates and releases mRNA

Question 4

B subunit RNA pol prokaryote

Answer 4

polymerization

Question 5

A subunit RNA pol prokaryote

Answer 5

interactions with regulatory proteins

Question 6

Sigma subunit RNA pol prokaryote

Answer 6

identifies start site

Question 7

Omega subunit RNA pol prokaryote

Answer 7

assembly of holoenzyme, recruits sigma factor

Question 8

Abortive transcripts

Answer 8

First 8-10 nucleotides are released by RNA Pol

Question 9

Kinetic proofreading

Answer 9

pol stalls after incorporating mismatch base
pyrophosphorlysis removes base

Question 10

Nucleolytic proofreading

Answer 10

pol backtracks to DNA, melting RNA
Intrinsic nuclease removes melted RNA

Question 11

Rifampicin

Answer 11

inhibits bacteria RNA synthesis by preventing promoter clearance, inhibiting elongation

Question 12

Actinomycin D

Answer 12

Intercalates into DNA and inhibits elongation
Acridine works similarly

Question 13

a-Amanitin

Answer 13

blocks pol II by preventing translocation

Question 14

Eukaryotic RNA Pol I

Answer 14

rRNA (18S, 28S, 5.8S)
Promoter: UCE core sequence
nucleolus

Question 15

Eukaryotic RNA Pol II

Answer 15

Genes encoding proteins (mRNA), miRNA, snRNA
Promoter: BRE, TATA box

Question 16

Eukaryotic RNA Pol III

Answer 16

tRNAs, 5S, rRNA
Promoter: Box A, B, C

Question 17

polymerase sensitivities to a-amanitin

Answer 17

found in deathcap mushrooms
Pol I insensitive
Pol II very sensitive
Pol III Moderately sensitive

Question 18

Pols have ____ affinity in eukaryotes but _____ affinity in prokaryotes

Answer 18

low, high

Question 19

TBP

Answer 19

TATA binding protein

Question 20

RNA Pol I initiation

Answer 20

2 UCE are bound by UBF which recruits SLI for RNA pol I recruitment and transcription

Question 21

TAF

Answer 21

TBP associated factors

Question 22

In RNA Pol III, what boxes are used for promotion of tRNA transcription?

Answer 22

A and B

Question 23

In RNA Pol III, what boxes are used for promotion of 5S RNA?

Answer 23

A and C

Question 24

What is required in RNA Pol II for initiation and elongation?

Answer 24

Phosphorylated c-terminal domain

Question 25

What are the transcription factors associated with RNA Pol II?

Answer 25

TFIIA-TFIIH

Question 26

What do silencers attract?

Answer 26

Histone deacetylases purpose is to make nucleosomes bind more tightly to DNA