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19 Cards in this Set
- Front
- Back
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RNA polymerase I
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45S Pre-rRNA Transcript
Nucleolus |
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RNA polymerase II
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mRNA, miRNA, U1,U2,U4,U5 snRNA
Nucleus |
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RNA polymerase III
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tRNA, 5S rRNA, U6 snRNA
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Holoenzymes
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Core RNA polymerase+
General Trans. Factors+ Specific Trans. Factors |
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Core RNA polymerase
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Enzyme consisting of multiple subunits
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General Transcription Factors
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Required for trans. of all genes
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Specific Transcription Factors
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Selectively regulate transcription of target genes
(trans-Acting Element) |
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cis-Acting Elements
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Specific SEQUENCES of DNA on the same molecule as gene
Ex. Promoter, Activator or Enhancer |
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trans-Acting Elements
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Regulatory PROTEINS derived from genes other than the target gene.
Ex. Specific Transcription Factors |
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RNA polymerase I
components |
a) Core Enzyme: 10-12 subunits
b) General Transcription Factor -1 TATA-binding protein(TBP) -3 TBP-associated Factors (TAFs) c)Specific Transcription Factor= UBF (upstream binding factor) -UBF stimulates activity of the RNA poly I holoenzyme |
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RNA polymerase II
components |
-Core RNA polymerase: 12 subunits
-General Trans. Factors(TFs): TFIID, TFIIB, TFIIF, TFIIE, TFIIH -Specific Trans. Factors: Activator proteins, Repressor proteins, Mediator proteins, Coactivators, Corepressors |
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TFIID
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Directs RNA poly to TATA box
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TFIIB
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Binds to TBP and Core RNA poly II
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TFIIF
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Stabilization of RNA poly II holoenzyme
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TFIIE
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Unwinding of DNA in promoter region
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TFIIH
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-Helicase activity unwinds DNA in the promoter region
-Protein kinase activity phosphorylates the C terminal domain of the Core RNA poly II |
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TATA Box
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-Consensus cis- Acting Element
-located -25 to -30 bp upstream of the trans. start site (found in most, but not all, promoters) -TATA(A or T)A |
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RNA Polymerase I GTF
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SL-1(Selectivity Factor 1)
-1 TATA binding Protein(TBP) -3 TBP-associated Factors(TAFS) |
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RNA Polymerase I STF
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-Upstream Binding Factor
-UBF stimulates activity of the RNA polymerase I holoenzyme |
