RNA processing

Question 1

Guanylyl transferase cleavage sites

Answer 1

γ from the RNA at the 5’ end
β and γ from the GTP being added
Forms 5’–5’ triphosphate

Question 2

Cleavage signal for poly-A tail addition

Answer 2

AAUAAA

Question 3

snRNPs

Answer 3

snRNA and protein complex responsible for splicing

Question 4

What type of bond is formed at the branch point?

Answer 4

2’-5’ phosphodiester a

Question 5

What do all introns begin and end with?

Answer 5

GU…….AG

Question 6

Where is the branch point located?

Answer 6

A located in pyrimidine rich sequence approx 50 base pairs from the 3’ end of the intron

Question 7

U1 function

Answer 7

Binds to 5’ splice site

Question 8

U2 function

Answer 8

Binds to branch site and forms part of catalytic primer

Question 9

U5 function

Answer 9

Binds to 3’ splice site, loops over to 5’ site

Question 10

U4 function

Answer 10

masks catalytic activity of U6

Question 11

U6 function

Answer 11

catalyzes splicing

Question 12

Lariat

Answer 12

Form of the spliced intron that is released

Question 13

SR proteins

Answer 13

Favor splicing

Question 14

hnRNP

Answer 14

inhibit splicing

Question 15

How can alternate splicing happen?

Answer 15

There are different sets of RNA binding proteins in different tissues

Question 16

Where do SR proteins bind?

Answer 16

Enhancer elements (exon splicing enhancers or intron splicing enhancers)

Question 17

Where do hnRNP bind?

Answer 17

Silencer elements (ISS or ESS)