Transcription Flashcards
What does it mean that RNA polymerase is a catalyst?
It speeds up the reaction by creating phosphodiester bonds the same way (with 3’-OH attacking 5’-Pi)
What direction does RNA polymerase work?
It creates RNA in the 5’->3’ direction by reading DNA in the 3’->5’ direction.
What are the three steps of Transcription?
Initiation, Elongation, Termination
What are the three steps of Initiation?
- RNA polymerase binds to promoter, 2. Polymerase melts DNA to create transcription bubble, 3. Polymerase catalyzes the first linkage between 2 rNTPs.
What is involved with the Elongation step?
Polymerase advances in the 3’-5’ direction down the strand, melting and linking.
What is involved in the termination step?
At the transcription stop site, polymeratse releases the completed RNA and dissocates from the DNA.
What is the function of RNA Polymerase I?
Makes rRNA (Don’t confuse with DNA Polymerase I!)
What is the function of RNA Polymerase II?
Makes mRNA, snRNA, miRNA. This has a C-Terminal Domain (Don’t confuse with DNA Polymerase II!)
What is the function of RNA Polymerase III?
Makes tRNA (Don’t confuse with DNA Polymerase III!)
What is the location of the Promoter and what does it look like?
TATA Box (AATAAA) is about 30bp before the transcription start site.
What is the location of the Promoter proximal elements?
PPEs are upstream of the DNA, but within ~1000bp
What is the location of Enhancer elements?
Enhancers are much farther upstream than the PPE, and are 10-50kbp long. These work through looping.
What is the function of α-amantin?
It is a non-competitive inhibitor of RNA polymerase II. It blocks chain elognation by preventing translocation. (Death Cap Mushroom)
What is the function of Rifampicin?
It is an antibiotic that binds bacterial RNA polymerases ad blocks the RNA exit channel.
Name as many components of RNA Polymerase II as you can (there are 6)
TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH
