RNA polymerases - Lecture 9 Flashcards
How many polymerases do prokaryotes have?
One RNA polymerase
How many polymerases do eukaryotic cells have?
Three
What are the three types of RNA polymerases in eukaryotes?
Polymerase I
Polymerase II
Polymerase III
What is polymerase I involved in?
Ribosomal RNA genes (rRNA)
What is RNA polymerase II involved in?
Protein coding genes (mRNA)
Small nuclear RNA (snRNA)
What types of eukaryotic RNA is RNA polymerase III used for?
Transfer RNA (tRNA),
rRNA and
snRNA
What is prokaryotic RNA polymerase made up of?
RNA polymerase holoenzyme
Sigma sub unit
2x alpha subunit
2x beta subunit
omega subunit
What does the sigma subunit do in prokaryotic RNA polymerase?
Recognises the promoter
It dissociates when the promoter is recognised and attached
What do the alpha subunits do in prokaryotic RNA polymerase?
Involved in assembly and activation
What do the beta subunits do in prokaryotic RNA polymerase?
Involved in catalysts and terminationW
What does the omega subunit do in prokaryotic RNA polymerase?
Involved in assembly and folding
Is required for some genes
What features do genes that make different RNA types have?
Different architecture
Use different RNA polymerases
What is the TFIID made up of?
Its a multi protein complex
Made up of TATA binding protein (TBP)
and TBP associated factors (TAFs)
What is the first stage of the assembly of the RNA polymerase II initiation complex?
TFIIA helps TFIID to bind
TFIIB sets the distance from TATA element to start site
What is the TBP DNA complex?
From the underside of the beta sheet surface the TBP has contact with the DNA minor groove