RNA Stability Control

Question 1

Which direction does mRNA degradation proceed? Why?

Answer 1

3’ to 5’. The 5’ cap can’t be degraded

Question 2

What triggers rapid degradation of mRNA?

Answer 2

When the polyA tail gets too short, about 30 nucleotides

Question 3

How does a short polyA tail trigger degradation of mRNA?

Answer 3

Triggers decapping so the transcript gets degraded rapidly from both ends

Question 4

How does the length of the polyA tail initially added to the transcript affect its stability?

Answer 4

Longer polyA tails will lead to the transcript being stable for longer

Question 5

How can RNA stability be regulated?

Answer 5

Protein binding, changing the length of the polyA tail, cleaving mRNA

Question 6

How can the degradation of mRNA be sped up?

Answer 6

Cleaving the mRNA, being an exonuclease, or recruiting an exonuclease

Question 7

How can the degradation of mRNA be slowed down?

Answer 7

Repress degradation from exonucleases, recruit polyA polymerase

Question 8

Why does cleavage of the mRNA lead to rapid degradation?

Answer 8

There is a 5’ end that is no longer protected by the cap, so it gets degraded quickly