Gene Expression 2 Flashcards
What does transcriptional control involve?
- which genes are transcribed
- their rate of transcription
Why are introns important?
What is a gene?
A transcriptional unit composed of structural information coding for a protein and regulatory sequences giving instructions for expression
What does the 5’ regulatory sequence control?
transcription initiation (gene promotor) (piece of DNA)
What type of polymerase helps to transcribe genes into proteins?
RNA polymerase II
What is RNA polymerase II made up of?
- core enzyme that recognises DNA, pulls it apart and makes a copy of it
- lots of proteins associated with to that helps it carry out its job (RNA Pol II holoenzyme)
What is a TATA box?
- a highly conserved sequence motif in a promoter which highlights if a start sequence (ATG) is meaningful
- basal machinery factors bind to it and unwind the DNA
What is the protein that binds to the TATA box?
TATA binding protein (TBP)
What does TFIID consist of?
- TBF
- TAFs (TBP associated factors)
What is TFIIDs major role?
to recruit RNA polymerase to the start site
How does TFIID recruit RNA pol II?
-TBP distorts promoter DNA to almost 90 degrees
What is TFIIH involved in
-DNA helices activity (unwinds DNA template)
-protein kinase activity (phosphorylates (CTD)
-releases Pol II from general transcription factors
(once this happens TFIID remains to promote re-initiation)
What is the basal level of transcription?
initiation complex assembly via stepwise binding of the general transcription factors
What is activated transcription?
transcription and gene specific transcription factors
What are transcriptional activators?
proteins that recognise a sequence within DNA and make protein protein interactions with RNA polymerase and telling it it is time to make RNA
