Eukaryotic Transcription Flashcards
What is monocistronic?
mRNA with a single cistron
Are most eukaryotic genes monocistronic or polycistronic?
Monocistronic
What does transcription from the eukaryotic genes produce?
Immature, pre-mRNA which gets post-transcriptionally processed to produce mature mRNA
Where does mature mRNA gets translated?
In the cytoplasm
What do eukaryotes have that makes them so complicated?
3 types of RNA (5 in plants), gazillions of more proteins in transcription initiation, exons and introns in their protein CDS, another gazillion of proteins for RNA processing, even their DNA is packaged in a more complex way
What is the function of enhancer elements?
Controls transcription efficiency
What is an exon?
Part of CDS which gets transcribed to RMA and encodes the protein
What is an intron?
Part of CDS which gets transcribed but does not code for protein is found in between the exons of the CDS
What are UTRs?
Regions of a gene that are transcribed, but not translated, are found 5’ and 3’ of the protein CDS
What are the 2 parts of class II promoter?
- Core promoter: 6 elements
- upstream element
What is the function of class II promoter?
Points RNA polymerase to the correct direction for transcription
What does the general transcription factors (GTFs) do?
They help RNA polymerase II interact with the core promoter elements
What are the 6 GTFs that are used to initiate transcription from the class II promoter?
GTFIIA - GTFIIH
What is the function of activator proteins?
They further regulate eukaryotic transcription
What is the function of the mediator protein?
It bridges the interaction between activator or enhancers and the proteins bound to the core promoter elements (RNA polymerases, GTFs, etc.)
What is the benefit of having multiple activators or enhancers?
It allow cells to control transcription more precisely.
What does the protein do to perform their function?
They interact with one another (protein-protein interaction) and with other parts of DNA (protein-DNA interaction)
What are the two enzymatic activities of TFIIH?
helicase and kinase
What is helicase activity?
TFIIH unwinds DNA using its XPB and XPD subunits
What is kinase activity?
TFIIH phosphorylates the 5th Serine of the RNA polymerase II C-terminal domain repeat
What is RNA polymerase II CTD?
A repeat of 7 amino acid sequence, YSPTSPS
When does most of RNA processing happen?
During elongation
What allows RNA polymerase II to enter the elongation phase?
Phosphorylation of RNA polymerase II
What is phosphorylated in RNA polymerase II CTD?
5th Serine of every repeat
What are the first two amino acids at the start of an intron?
GU
What is the branching point?
Adenine
What are the conserved nucleotides?
5’ GU and 3’ AG
What are the last two amino acids of an intron?
AG
What is the branch point sequence?
YNYURAY
