Control of Gene Expression 2

Question 1

What does alternative splicing produce?

Answer 1

Forms of proteins from the same gene

Question 2

Alternative splicing can be controlled through?

Answer 2

negative and positive

Question 3

How is RNA splicing regulated negatively?

Answer 3

Prevents splicing machinery access to splice site

Question 4

How is RNA splicing regulated positively?

Answer 4

Activating molecule that recruits and helps direct splicing machinery

Question 5

RNA cleavage yields

Answer 5

protein with longer or shorter C-terminus

Question 6

Long RNA transcript

Answer 6

intron sequence removed byRNA processing

translation occurs…. membrane bound antibody

Question 7

Short RNA transcript

Answer 7

intron sequences not removed bc acceptor splice junction is missing
translation
secreted antibody

Question 8

how does mRNA leave nucleus?

Answer 8

through pores

Question 9

How does mRNA travel?

Answer 9

1. uses cytoskeletal motors
   - anchor proteins hold mRNA in place
2. random movement
3. random movement + degeneration (RNA not trapped is degraded)

Question 10

What does mRNAs poly-A-tail provide?

Answer 10

confers stability

Question 11

What is poly-A tail shortened by?

Answer 11

exonuclease

Question 12

globin mRNA 1/2 life

Answer 12

10 hours

Question 13

most mRNAs 1/2 life

Answer 13

only 30 mins

Question 14

What does shortening of poly-A tail act as?

Answer 14

timer

Question 15

What happens when mRNA tail reaches 25 nucleotides?

Answer 15

two pathways converge to degrade mRNA

Question 16

1- decapping regulation by RNA stability

Answer 16

exposed mRNA degraded from 5’ end (5’ serves to protect RNA from RNA degrading enzymes)

Question 17

2- mRNA degraded from?

Answer 17

3’ end through poly A tail and into coding region

Question 18

two ways of mRNA regulation?

Answer 18

1 repression of translation

2. RNA degradation
   - control of RNAs involved in iron metabolism