4 RNA Synthesis

Question 1

what does RNA pol 1 transcribe?

Answer 1

rRNA (nucleolar)

Question 2

what does RNA pol 2 trasncribe?

Answer 2

pre-mRNA (heterogenous nuclear RNA)

Question 3

what does RNA pol3 trans?

Answer 3

tRNA, 5s rRNA and other small RNA genes

Question 4

the different RNA polymerases can be distinguished from one another by their sensitivity to what?

Answer 4

alpha-amanitin

Question 5

in the transcription of rRNA, what promotes the binding of RNA pol1 to the regulatory region

Answer 5

Factor B and Factor S proteins

Question 6

in the trans of 5S rRNA, what proteins allow RNA pol 3 to begin transcribing?

Answer 6

TF3A and TF3C bind the promoter which permits recruitment of TF3B and finally pol3

Question 7

where are the promoters for RNA pol3 typically found?

Answer 7

within the gene

Question 8

what are enhancers?

Answer 8

DNA sequences taht can up regulate transcription of neighboring genes
-located upstream, downstream, or within a gene

Question 9

What is the purpose of a TATAA box?

Answer 9

this is the site where the polymerase binds and being transcribing.

Question 10

name the order of proteins recruited to the TATAA box?

what is this group of proteins called?

Answer 10

1. TF2D
2. TF2B
3. TF2H
4. TF2E and RNA pol2 silmultaneously
   - basal transcription factors (required for all genes)

Question 11

what are the three major steps in mRNA processing?

Answer 11

1. capping
2. polyadenylation
3. splicing

Question 12

what is the 5’ cap at the end of eukaryotic mRNA composed of

Answer 12

7 methyl guanosine

Question 13

after a gene is transcribed, what happens at the 3’ end of mRNA?

Answer 13

a poly A tail is added

Question 14

what sequence is found 10 to 30 nt up from the poly A tail?

Answer 14

AAUAAA

Question 15

what is recognized by the cleavage and poly-adenylation specificity factor (CPSF)?

Answer 15

AAUAAA

Question 16

are introns or exons found in mature mRNA

Answer 16

exons

Question 17

what is the stepwise process of mRNA splicing?

Answer 17

1. cleavage at 5’ exon intron junction and formation of a lariat
2. circulization of intron and nucleophilic attack
3. cleavage of 3’ intron exon junction and ligation of neighboring exons

Question 18

where does splicing take place?

Answer 18

spliceosomes, large ribonucleotide protein particles akin to ribosomes

Question 19

what type of RNA do ribosomes contain?

Answer 19

small nuclear RNA (SNRNA’s) U1, 2, 4, 5, 6

Question 20

in general, what is a thalassemia?

Answer 20

abnormalitys of Hb proteins, mainly a deficiency in one of the subtypes

Question 21

what is the correlate between splicing and thalassemia?

Answer 21

1/4 of all mutations in the globin gene are in regions that specify correct splicing

Question 22

what is alternative splicing?

Answer 22

ways to splice a common transcript in a way that it produces multiple unique protein products. this is found in different cell types

Question 23

what is rifampacin?

Answer 23

blocks initiation of bacterial RNA synthesis

Question 24

what is actinomycin?

Answer 24

binds to double helical DNA and prevents it from being transcribed

Question 25

recite the stepwise process of preparing cDNA from mRNA

Answer 25

1. anneal primers
2. use RT to make DNA copy
3. treat with alkali to degrade RNA
4. use DNA polymerase to synthesize complimentary DNA strand (will use the 3’ hairpin loop as a template)
5. treat with S1 nuclease to cleave the loop