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Biol321 Molecular Genetics
Handout 9
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Yeast RNA polymerase II subunits
PTSPSYS CTD
Epitope tagging
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Prokaryotic RNA polymerase
Eukaryotic RNA polymerase
RNAP from T. aquaticus
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Initiation of transcription by RNA
polymerase II
UCE
-200 -150 -100 -50 +1 +50 +100 +150 +200
-45 +20
-25 InrUps tream Elements
Core promoter
RNA Pol I
RNA Pol II
RNA Pol III
RNA polymerase promoters
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Initiation at RNA Pol. II promoter
Initiator sequenceYYCARR
-25 box = TATA boxTATAWAW
-25 InrUps tream Elements
RNA Pol II
TFIID: (~800kD, larger than RNA pol II at ~600kD)
TBP
TAFs(9 to14)
TBP = TATA binding protein
TAF = TBP associated factors
TATAAATATAAA
mRNA
Building the preinitiation complex (PIC)
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TBP bends DNA ~80o and forces open the minor groove
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-200 -150 -100 -50 +1 +50 +100 +150 +200
-25 InrUps tream elements
RNA Pol II
Initiation at RNA Pol. II promoter
TF TF TF
- + +
TAF
TBPA B
F
EH
Stimulation of transcription by activator binding to an enhancer
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The Mediator Complex Links Activation Domains to RNA Pol II
Activation of transcriptionBy transcription factors (TFs),
activator, and coactivator proteins
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Initiation at RNA Pol. I promoter
Core Promoter
Upstream Control Element
(CP)
Initiation at RNA Pol. I promoter
(CP)
RNAP I
UB
FU
BF
UB
FU
BF
SL1TIF-IATIF-IC
OnUBF UBF Binds (as a dimer) CP and UCE
SL1 SL1 (in humans) ≡ TIF-IB in mouseTIF-IATIF-IC Recruitment of RNA Pol. I
RNAP I RNA Pol. I
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RNA polymerase III promoters
Initiation at RNA Pol. III promoter
TFIIIC Binds box A and box C
Binds to TFIIIC
Recruitment of RNA Pol. III
RNAP III RNA Pol. III
TFIIIA
TFIIIB
Recruit TFIIIB
TFIIIC TFIIICTFIIIA
TFIIIB
RNAP III
On
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Regulatory
Holoenzymes with different promoter-binding specificity
SigmaFactor Promoters Recognized Promoter Consensus
-35 Region -10 Region70 (rpoD) Most genes TTGACAT TATAAT32 (rpoH) Genes induced by heat shock TCTCNCCCTTGAA CCCCATNTA
-24 Region -12 Region54 (rpoN) Genes for nitrogen metabolism and CTGGNA TTGCAother functions