Transcription
type

Steady
State
Levels

rRNA

83%

58%

High

tRNA

14%

10%

High

mRNA

3%

32%

Very Low

Synthetic
Capacity

Stabil...


RNA polymerase core enzyme is a
multimeric protein a 2 ,b, b’, w



The b’ subunit is involved in DNA
binding



The ...


The a subunit acts as scaf fold on
which the other subunits assemble.



Also requires s-factor for initiation –
forms...
Site of DNA binding and RNA polymerization
5’

Promoter

Transcribed region

terminator 3’


Standard genes – s 70



Nitrogen regulated genes – s 54



Heat shock regulated genes – s 32
Closed complex
Open complex

Primer formation
Disassociation of
s-factor
3’end tends to be AU rich easily to disrupt during pausing.
Leads to disassembly of RNA polymerase complex


rho is an ATP-dependent helicase



it moves along RNA transcript, finds
the "bubble", unwinds it and releases
RNA cha...
type

Location

Products

RNA polymerase I

Nucleolus

rRNA

RNA polymerase II

Nucleoplasm

mRNA

RNA polymerase III

Nuc...
• RNA polymerase I, II, and III
• All 3 are big, multimeric proteins (500-700
kD)
• All have 2 large subunits with sequenc...


Contain AT rich concensus sequence located
–19 to –27 bp from transcription star t (TATA
box)



Site where RNA polyme...


TFAIIA, TFAIIB – components of RNA
polymerase II holo-enzyme complex



TFIID – Initiation factor, contains TATA
bindi...
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Transcription

  1. 1. Transcription
  2. 2. type Steady State Levels rRNA 83% 58% High tRNA 14% 10% High mRNA 3% 32% Very Low Synthetic Capacity Stability
  3. 3.  RNA polymerase core enzyme is a multimeric protein a 2 ,b, b’, w  The b’ subunit is involved in DNA binding  The b subunit contains the polymerase active site
  4. 4.  The a subunit acts as scaf fold on which the other subunits assemble.  Also requires s-factor for initiation – forms holo enzyme complex
  5. 5. Site of DNA binding and RNA polymerization
  6. 6. 5’ Promoter Transcribed region terminator 3’
  7. 7.  Standard genes – s 70  Nitrogen regulated genes – s 54  Heat shock regulated genes – s 32
  8. 8. Closed complex Open complex Primer formation Disassociation of s-factor
  9. 9. 3’end tends to be AU rich easily to disrupt during pausing. Leads to disassembly of RNA polymerase complex
  10. 10.  rho is an ATP-dependent helicase  it moves along RNA transcript, finds the "bubble", unwinds it and releases RNA chain
  11. 11. type Location Products RNA polymerase I Nucleolus rRNA RNA polymerase II Nucleoplasm mRNA RNA polymerase III Nucleoplasm rRNA, tRNA, others Mitochondrial RNA polymerase Mitochondria Mitochondrial gene transcripts Chloroplast RNA polymerase Chloroplast Chloroplast gene transcripts
  12. 12. • RNA polymerase I, II, and III • All 3 are big, multimeric proteins (500-700 kD) • All have 2 large subunits with sequences similar to β and β' in E.coli RNA polymerase, so catalytic site may be conserved
  13. 13.  Contain AT rich concensus sequence located –19 to –27 bp from transcription star t (TATA box)  Site where RNA polymerase II binds
  14. 14.  TFAIIA, TFAIIB – components of RNA polymerase II holo-enzyme complex  TFIID – Initiation factor, contains TATA binding protein (TBP) subunit. TATA box recognition.  TFIIF – (RAP30/74) decrease af finity to non-promoter DNA

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