Transcription II Flashcards
differences in eurkaryotic transcription
- ) enhancers and repressors can be really far from the promoter region
- ) TATAA box
TATAA box
proteins bind to this region and they tell pol II which strand is coding and which strand is template, helps polymerase locate exact transcriptional starting spot, not all genes have TATAA box, located -25 upstream of transcriptional starting point
GC box
when no TATAA box (and usually not CCAAT box) the GC box helps bring polymerase to promoter and orient it, not as precise as TATAA box though, upstream of TATAA box around -40bp from stat of transcription, Sp1 binds here
CAP site
regulates efficiency in which TATAA box brings in factors to recruit polymerase, downstream of TATAA box
what happens at the TATAA box
- ) IID binds–protein recognizes TATA sequence and binds by straddling the DNA
- ) IIA binds upstream of IID–stabilizes interaction with DNA
- ) IIB then binds to IID–function is to interact with IIF (attached to pol II)
- ) IIE/H and J arrive
* *collectively known as the pre-initiation complex** - ) 8-9 nucleotide strand synthesized, IIF falls off and elongation factors bind to complex
IIE/H
helicase activity so begins to unwind DNA, IIH also has phosphorylation activity–phosphorylates pol II to ramp up activity
enhancers
facilitate formation of the PIC, can change position and orientation of enhancer site and it still retains its function, can’t be too close to the promoter region though
repressors
inhibit formation of the PIC
transcription factors
elements that bind to DNA that +/- the rate of transcription but CAN’T be part of the PIC, repressors or enhancers, can be tissue specific, can function as dimers, can interact directly with the PIC
glucocorticoid receptor
binds GC and regulates the inflammatory response
coactivators/corepressros
other elements brought in by transcription factors to regulate transcription
proximal promoter
region of the promoter close to the transcription start site, contains TATA and CCAAT boxes
distal promoter
more distant upstream promoter
TATA binding protein (TBP)
part of IID
cis elements
where transcription factors bind