lecture 10 recap

Question 1

if we lose cap or polyA tail mRNA wont be

Answer 1

circular

Question 2

bulk of mRNA is degraded by

Answer 2

exonucleases

Question 3

decapping enzymes give an end for the exonucleases to access e.g.

Answer 3

DCP1 and DCP2

Question 4

deadenylases e.g. Ccr/Not complex remove what

Answer 4

polyA tail

Question 5

endonucleases cut the mRNA in the

Answer 5

middle e.g. argonaute, Swt1 and Smg6

Question 6

the exosome works from

Answer 6

3’ to 5’

Question 7

XRN1 works from

Answer 7

5’ to 3’

Question 8

when polyA gets to short it is signalled for

Answer 8

degradation

Question 9

signals for premature degradation

Answer 9

AU rich elements in 3’ UTR
nonsense codon
c-fos major coding determinant
miRNA

Question 10

deadenylation independent decay:
1. rps28B binds to mRNA and it recruits what

Answer 10

Edc3 which promoted decapping

Question 11

2. endonucleases cut mRNA in the middle allows exosome or XRN1 to degrade without removing

Answer 11

cap or poly a tail

Question 12

NMD =

Answer 12

nonsense mediated decay

Question 13

how can the cell recognise if the stop codon is in the right place

Answer 13

due to the distance bwteen it and the splice site

Question 14

if the distance is greater than __ nuceltides then its an NMD target

Answer 14

55

Question 15

what are exon junction complexes

Answer 15

proteins deposited onto the exons after splicing

Question 16

they remain on the mRNA until the the first round of translation when they are removed by what

Answer 16

the ribosome

Question 17

if its a premature stop codon EJCs will remain downstream which proteins from the EJC are then recruited

Answer 17

UPF proteins and they interact with the RNA degradation

Question 18

RNAi =

Answer 18

RNA interference

Question 19

siRNA

Answer 19

small inhibitory RNA

Question 20

miRNA

Answer 20

micro RNA

Question 21

RISC

Answer 21

RNA induced silencing complex

Question 22

si RNA and miRNA are how long

Answer 22

21-23 nucleotides

Question 23

siRNA are complimentary to the

Answer 23

target RNA

Question 24

miRNA are

Answer 24

imperfectly complementayr to a
traget DNA

Question 25

si RNA leads to

Answer 25

degradation

Question 26

miRNA leads to block in

Answer 26

translation

Question 27

drosha and dicer do what

Answer 27

cute the pre miRNA into miRNA

Question 28

ds RNA is cut by dicer to

Answer 28

siRNA

Question 29

they cur RNA is then

Answer 29

unwound into single strands

Question 30

siRNA bind to

Answer 30

argonaute

Question 31

argonaute is the

Answer 31

nuclease

Question 32

miRNA binds to the mRNA in the

Answer 32

3’ UTR and blocks translation

Question 33

3’ UTR length changes
longer 3’ UTR =

Answer 33

more regulation

Question 34

what cells have shorter 3’ utr

Answer 34

proliferating cells

Question 35

what cells have longer 3’ utr

Answer 35

embryonic development cells as cells get differentiated and things slow down so need more regulation