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20 Cards in this Set
- Front
- Back
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what does RNA polymerase do |
an enzyme that synthesises RNA using a DNA template |
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what is the promoter region |
a region on DNA where RNA pol binds to initiate transcription |
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what is the startpoint |
the position on DNA corresponding to the first base incorporated into RNA (begins at +1) |
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what is terminator |
a sequence of DNA that causes RNA polymerase to terminate transcription |
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how does RNA polymerisation take place |
the 3'OH group of the last ribonucleotide added to the chain reacts with the incoming ribonucleoside 5' triphosphate |
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what are the 3 RNA pols and what do they trancribe |
rna pol 1 - 14 subunits - rRNA - nucelolus rna pol 2 - 12 subunits - mRNA-nucleoplasm rna pol 3 - 17 subunits - tRNA - nucleoplasm |
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what are the eukaryotic RNA polymerases subunits that are present in all 3 RNA pols |
rpb 5, rpb6, rpb8, rpb 10, rpb 12 |
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which is the subunit of TF11D that binds to the TATA box |
TBP - (TATA binding protein) |
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which groove of DNA does TBP interact with TATA |
minor groove |
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what are the additional proteins that comprise TF11D |
TAFs - TBP associated factors |
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how many subunits of TAFs does TF11D contain |
13 |
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explain the processes of transcription inititation process |
1. TBP bends the TATA box around the C terminal domain of TF11B. 2. the N-terminal domain of TF11B brings the complex to RNA pol 11 and positions the transcription inititation site in the active site of rna pol 11. 3. the rna pol11-tf11b-promoter complex recuits tf11e, which then recuits th11h 4. the helicase activity of tf11h unwinds DNA in the vicinity of the initiation site 5. tf11f captures the non-template strand after unwinding 6. template strand descends to the active site |
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what is abortive transcription |
it is the formation of short transcripts which are released |
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what is promoter escape |
chain extension beyond 7 ribonucleotides triggers tf11b release and the formation of transcription elongation complex |
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what plays a key role in the transition from the initiation complex to the elongation complex |
carboxyl terminal doman (CTD) of the largest subunit of RNA pol 11 (Rbp1) |
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which transcription factor reactivates RNA pol 11 |
tf11s |
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describe the structure of RNA pol 1 |
has a bipartite promoter RNA pol 1 promoter consists of core promoter and UPE (upstream promoter element) |
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how does initiation take place with RNA pol 1 |
UBF1 wraps DNA around a protein structure that brings the core promoter and the UPE is close proximity SL1 includes the factor TBP that binds to the TATA box in all 3 polymerases RNA pol1 binds to the UBF1-SL1 complex at the core promoter |
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how does initiation take place in RNA pol 111 |
RNA pol 111 uses upstream and downstream promoters RNA pol 111 has 3 types of promoters - 2 internal |
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how does inititaion complex form in rna pol 111 internal promoters |
internal promoters have short consensus sequences located within the transcription unit and initiates transcription at a fixed distance upstream TF111A and TF111C bind to the consensus sequence and enable TF111B to bind to the start point TF111B contains TBP as one subunit and enables RNA polymerase to bind. |
