TRANSCRIPTION

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TRANSCRIPTION
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TRANSCRIPTION RNA STRUCTURE, SYNTHESIS, AND
FUNCTION Kinds of RNA transfer, ribosomal,
messenger Structure single-stranded, partial
double-strand regions, H bonds RNA
Polymerase Promoter reading frame, closed
complex, open complex, initiation Specificity
Factor sigma Polymerization single strand 5' gt
3' Termination Eukaryotic mRNA exon, intron,
capping, poly A, splicing RNA POLYMERASE
ACTIVITY SUBJECT TO Specificity
factors sigmas which recognize specific
promoters Accessory factors repressors,
activators, anti-sense RNAs, anti-sigma
factors
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GENE PRODUCTS INCLUDE PROTEIN OR RNA GENES
(DNA)
TRANSCRIPTION BY RNA POLYMERASE
mRNA
or rRNA or tRNA
TRANSLATED INTO PROTEINS
FUNCTION IN PROTEIN SYNTHESIS
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URIDINE TRIPHOSPHATE - UTP
ESTER
URACIL N - GLYCOSIDE BOND
ANHYDRIDES
NUCLEIC ACID BASE
RIBO NUCLEOSIDE
RIBO NUCLEOSIDE TRIPHOSPHATE OR RIBONUCLEOTIDE
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RNA STRUCTURE
SINGLE STRANDS
COMPLEMENTARY REGIONS FOLD BACK PARTIALLY DOUBLE-
STRANDED
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POLYCISTRONIC
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RNA POLYMERASE
SUBUNITS a2 bb' s
CORE - POLYMERIZATION
INITIATION (SPECIFICITY) FACTOR
HOLOENZYME
FUNCTIONS RECOGNIZE/BIND SUBSTRATES - ATP,
GTP, UTP, CTP PROMOTER - SITE IN
DNA TEMPLATE - TRANSCRIBES NUCLEOTIDE SEQUENCE
INITIATION OF POLYMERIZATION
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PROMOTER - SITE IN DNA RNA POLYMERASE BINDS
STARTS TRANSCRIPTION
-35
-10
1
5'
3'
3'
5'
5'
3'
3'
5'
ONE DNA STRAND IS TEMPLATE (TRANSCRIBED) RNA
SEQUENCE - COMPLEMENTARY TO LOWER DNA
STRAND IDENTICAL TO TOP STRAND (EXCEPT U FOR
T) RNA - POLYMERASE STARTS CHAINS
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RNA POLYMERIZATION
DNA TEMPLATE
3'
5'
3'
3'
5'
5'
NUCLEOTIDYL TRANSFER
3'
5'
NOTE 5' 3'

3'
3'
5'
5'
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GENE OR OPERON
PROMOTER
TERMINATOR
5'
3'
3'
5'
TRANSCRIPTION START
TRANSCRIPTION STOP
RNA POLYMERASE HOLOENZYME - CORE s
RNA POL
CLOSED COMPLEX
CORE s

OPEN COMPLEX

ATP/GTP/UTP/CTP
3'
5'
INITIATION
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PPi s
ATP/GTP/UTP/CTP
3'
5'
3'
POLYMERIZATION
5'

3'
5'
3'
5'

3'
5'

TERMINATION
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TERMINATOR STEM AND LOOP
COMPLETED mRNA
PROTEIN CODING REGION PROTEIN READING FRAME
5'
3'
UNTRANSLATED REGION
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EUKARYOTE M-RNA PROCESSING
1-TRANSCRIPTION START
TRANSLATION STOP
TRANSCRIPTION STOP
TRANSLATION START
DNA
POLY A ADDITION SITE
PROMOTER
NON - PROTEIN CODING INTRON
PROTEIN CODING EXON
PRIMARY TRANSCRIPT PRE-M-RNA
3'
5'
EXON
INTRON
5' CAPPING 3' POLY ADENYLATION
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5'
3'
CAP
SPLICING (SPLICEOSOME)
POLY-A
MATURE M-RNA
PROTEIN CODING REGION CONTIGUOUS CODONS
TRANSLATION
PROTEIN
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CAP
3'
CAP FUNCTIONS - STABILITY DIRECT RIBOSOMES TO
START CODON NEAREST CAP
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TRANSCRIBING RNA POLYMERASE II (YEAST) CUT AWAY

• ENTERING DNA BINDS CLEFT (POSITIVE CHARGES)
• CLAMP FOLDS OVER
• TEMPLATE AND NON - TEMPLATE STRANDS SEPARATED
• WALL BENDS DNA TEMPLATE 90o , EXPOSES RNA 3'
  END
• Mg2 ACTIVE SITE
• SUBSTRATE NTPs ENTER FUNNEL AND PORE
• RNA DNA 9 BP HYBRID
• RUDDER SEPARATES RNA DNA HYBRID

TRANSCRIPTION
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RNA POLYMERASE ACTIVITY

• SPECIFICITY - DEPENDS ON SIGMAs
• DIFFERENT SIGMA FACTORS ALLOW CORE ENZYME TO
  TRANSCRIBE DIFFERENT SETS OF GENES
• DIFFERENT SETS OF GENES HAVE DIFFERENT
  PROMOTERS
• E. COLI HAS 7 SIGMAs
• ACCESSORY PROTEINS MODULATE ACTIVITY OF RNA
  POLYMERASE AND SIGMA
• INCLUDE REPRESSORS AND ACTIVATORS
• ANTI - SENSE RNA
• ANTI - SIGMA FACTORS

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