Transcription and Regulation by RNA Pol II and I

Question 1

genes transcribed by RNAPIII are

Answer 1

housekeeping genes required under most conditions

Question 2

RNAPIII is a – subunit enzyme

Answer 2

17

some are unique and some shared with RNAPI/II

Question 3

What is a type 1 RNAPIII promoter?

what is it used for?

Answer 3

has an internal control region (ICR) - A box, intermediate element, C box

used for 5S rRNA and rRNA

Question 4

What is a type 2 RNAPIII promoter?

what is it used for?

Answer 4

A box and B box

tRNAs, VA RNA

Question 5

What is a type 3 RNAPIII promoter

what is it used for

Answer 5

distal sequence element that enhances transcription and a core promoter which has.a proximal sequence element and a TATA box (like RNAPII)

RNAse, P RNAs, U6, 7SK

Question 5

How is RNAPIII promoter elements different from RNAPI and II?

Answer 5

promoter elements of most genes are within the transcribed region

Question 6

RNAPIII functions together with # transcription factors:

Answer 6

3
TFIIIA, TFIIIB and
TFIIIC

Question 7

How does RNAPIII transcription initiation complex on a type 2 promoter occur?

Answer 7

1. TFIIIC binds to A and B box and helps place TFIIIB upstream of TSS
2. TFIIIB binds to TFIIIC
3. TFIIIB has TBP
4. RNAPIII recruited by TFIIIB and TFIIIB opens transcription bubble

Question 8

How does RNAPIII transcription initiation complex form on a type 1 promoter?

Answer 8

1. same as type 2 but its blocks A and C
2. TFIIIA (zinc finger protein) binds to ICR

to target 5S rRNA

Question 9

How does RNAPIII transcription initiation complex form on a type 3 promoter?

Answer 9

• PSE is recognized by comples: PSE-binding protein (PBP) + PSE TF + snRNA activating complex (SNAPc)
• TFIIIB binds to TATA box (upstream of TSS)
• RNAPIII binds

Question 10

How does the RNAPIII promoter type 2 demonstrate its product?

Answer 10

A box corresponds to D loop of tRNA and B box corresponds to T loop of tRNA

Question 11

How does RNAPIII stop?

Answer 11

after adding 4-5 U residues in a row (oligo U to oligo dA is weak bp so this causes destabilization signal)

Question 12

RNA polymerase I transcribes the genes that encode the structural RNAs for the

This happens in the

Answer 12

ribosomal subunits

NUCLEOLUS

Question 13

Ribosomal assembly is…
this happens in…

Answer 13

incorporating rRNA made by RNAPI and RNAPIII 5S rRNA and ribosomal proteins

nucleolus

Question 14

The ribosomal DNA (rDNA) is
transcribed into a — (45S pre-rRNA), which is then cleaved into 28S, 18S, and 5.8S rRNAs.

Answer 14

large RNA molecule

Question 15

What are the elements in the RNAPI promoter?

Answer 15

• UCE: upstream control element
• core promoter

Question 16

What is SL1?

Answer 16

protein containing TBP that binds to core promoter of RNAPI promoter
- sufficient for basal transcription

adds promoter specificity

Question 17

What are UBFs?

Answer 17

upstream binding factors
- proteins that bind to UCE in RNAPI promoter
- promotes decondensation of rRNA chromatin
- interacts with SL1 at rDNA promtoter
- binds at many sites along the gene

Question 18

Similarities and differences between RNAPI/II/III?

Answer 18

• A common feature of the basal transcription machinery used by Pol I, II and III is the requirement for a TBP-containing
  transcription factor complex
• the combination of TBP-associated factors (TAFs) is polymerase-specific