Eukaryotic Transcription Flashcards
All three eukaryotic RNA polymerases contain – large subunits and – smaller subunits
2 large and 10-14 small
transcribe precursor rRNA
RNA pol I
transcribe mRNA and others
RNA pol II
transcribes tRNA and rRNA
RNA pol III
promoter regions contain a consensus sequence called
TATA box
• TATA Box:
-Located at about – upstream of start site
-35 to -25 region
TATA box is bound specifically by – of the TFIID complex
TATA box Binding Protein
TATA box acts similar to a – to position RNA polymerase II for transcription initiation
prokaryotic promoter
There are many proteins, –, that associate with the polymerase. They position polymerase molecules at transcription start sites and help to melt the DNA strands so that the template strand can enter the active site of the enzyme. Required for synthesis of RNA from most genes.
general transcription factors (GTF)
GTF + RNA pol II =
transcription preinitiation complex
TBP is a monomeric protein that is highly conserved between species ( – identical between yeast & humans in the conserved domain).
80%
TBP Has many – that
line up and fit in the minor groove of DNA, bending the DNA structure.
beta sheets
In prokaryotes, – causes the DNA to bend while in Eukaryotes, TBP is responsible.
RNA Pol
TBP (TATA-box binding protein) – to the TATA box.
recognizes and binds
TBP is a subunit of TFIID (transcription factor), which is also composed of about 11
TAF (TBP associated factors
Once TBP has bound to the TATA box, – can bind
TFIIB
• Binding of TFIIB positions a – to bind to the start site.
preformed PolII-TFIIF complex
– is the C-terminal domain of a subunit of RNA Pol II.
CTD
TFIIF recruits
TFIIE
TFIIE recruits
TFIIH
Once TFIIE & TFIIH binds, the preinitiation complex formation is complete and Pol II becomes –.
active
TFIIH is a multisubunit protein complex that has
– – : unwinds, separates, DNA for Pol II using ATP
– – activity: it phosphorylates CTD of Pol II
helicase and kinase
The active form of Pol II is phosphorylated (by TFIIH) at its –
CTD
With the start of transcription, – remains bound to the TATA box while the other GTF dissociate and are released.
TFIID
– serves as a trigger
to release polymerase from GTFs.
Phosphorylation
In addition, phosphorylation of RNA polymerase II CTD allows – to assemble on its tail
RNA-processing
protein
The carboxyl terminal domain (CTD) contains – that are repeated multiple times
7 aa
Consensus sequence of CTD:
Tyr-Ser-Pro-Thr-Ser-Pro-Ser
CTD yeast
27 repeats
CTD humans
52 repeats
The CTD is critical for –, and at least 10 copies of the repeat
must be present for yeast to survive.
viability
Many Ser and Tyr residues are modified by phosphorylation, especially the –
5th Ser
