RNA Processing Regulation

Question 1

Does regulation of RNA processing occur in prokaryotes or eukaryotes?

Answer 1

Only in eukaryotes, no RNA processing occurs in prokaryotes

Question 2

What is alternative splicing?

Answer 2

The same pre-mRNA is spliced in different ways

Question 3

Is alternative splicing rare?

Answer 3

No, it happens in 60% of human genes and is common in higher eukaryotes

Question 4

Does the complexity of an organism correlate with the number of genes?

Answer 4

No

Question 5

Does number of genes = number of proteins encoded?

Answer 5

No

Question 6

Why is alternative splicing advantageous?

Answer 6

It allows an organism to make more proteins with fewer genes

Question 7

What are the different forms of the same gene present in different tissues called?

Answer 7

Isoforms

Question 8

How different will the functions of splicing variants be from each other?

Answer 8

Their functions will still be similar but may be slightly different from tissue to tissue

Question 9

What are the 2 mechanisms by which alternative splicing occurs?

Answer 9

1. Splicing activators increase spliceosome binding

2. Splicing repressors can block spliceosome binding

Question 10

How do splicing activators cause alternative splicing?

Answer 10

They can recruit the spliceosome to a less favourable 5’ splice site, so the pre-mRNA gets spliced there instead of where it would usually splice

Question 11

How do splicing repressors cause alternative splicing?

Answer 11

Block a more favourable 5’ splice site from spliceosome binding so it splices at a less favourable site

Question 12

What are multiple 3’ cleavage sites?

Answer 12

Different possible sites where the RNA transcript is cut off from RNA polymerase

Question 13

How does cleavage occur at different 3’ cleavage sites?

Answer 13

Through the use of activators and repressors

Question 14

Are multiple cleavage sites rare in humans?

Answer 14

No, occurs in about 50% of genes