Unit 2: Mechanisms of RNA Polymerases Flashcards
What 2 transcription factors does RNA Pol II need?
- TFIID
- TFIIH
What is TFIID and what does it do?
TFIID: TATA box binding protein (TBP) + TAF
-recognizes TATA box and starts transcription
What is TFIIH and why is it important?
TFIIH: DNA helicase and Pol II CTD kinase function
-it phosphorylates the CTD domain which signals the CTD domain to start making RNA
What is the CTD domain in RNA Pol II?
-C terminal domain
-phosphorylation of this domain starts RNA transcription
-important for co-transcriptional mRNA processing
What are the 2 regions for the promoter in RNA Polymerase I?
- Upstream element (UPE)
- core
What 3 transcription factors are needed for transcription to start in RNA pol I?
- Upstream activating factor (UAF)
- Core Factor (CF)
- TATA box binding protein (TBP)
Where does rRNA transcription occur?
Nucleolus
What is the spacer region i n the rRNA gene of RNA pol I?
A space where transcription does not occur
What are the steps for RNA Pol I?
- Transcription
- Modification
- Processing
snoRNA
-small nucleolar RNA
-base pairs with specific regions of pre-rRNA and will recruit enzymes to modify pre-rRNA
Why is rRNA. modification important and how does it happen?
-Without modification the rRNA is not functional
-It happens co-transcriptionally (modification and transcription happens at the SAME time)
In RNA Pol III where is the promoter, what is it called, and what happens to it?
-Promoter is downstream (to the right) of TSS
-called Internal Promoter
-The promoter gets transcribed
-ONLY FOR tRNA and 5sRNA
Which RNA polymerase is the most active in the cell
RNA Polymerase I
What is 5’ capping used for?
Signals/marks RNA for translation into protein
-those with no cap do not get translated
