Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
Give the elements present in eukaryotic promoters. |
Polymerase, enhancers, activators, repressors, mediators.
TATA box Initiator (Inr) element Downstream core promoter element (DPE) BRE element
Enhancer & UAS Silenecer & URS |
|
|
What is the function of the TATA box?
|
Core promoter sequence, binding site of GTFs or histones. TBP binds to TATA box sequence which unwinds the DNA.
|
|
|
What is the function of the Inr element?
|
Same function as the TATA box, however binds TFIID. Depends on correct spacing between the Inr and DPE.
|
|
|
What is the function of the DPE?
|
Initiates gene transcription by RNA pol II. DPE binds TFIID. DPE dependent basal transcription depends highly on the spacing between DPE and Inr.
|
|
|
What is the function of the BRE?
|
TFIIB recognition element. Found in the promoter region of most genes in eukaryotes.
|
|
|
How are reporter genes used to analyse promoter sequences?
|
To work out whether a particular promoter is activated or not, and whether a certain gene has been taken up and expressed by the cell. 1. Different versions of the promoter sequence are generated using recombinant DNA techniques to truncate the DNA making shorter sequences in a 5' deletion series. 2. Each variant is ligated into the plasmid vector that is carrying the reporter gene. 3.Each type of plasmid is separately transfected into cultured cells. |
|
|
How many major RNA polymerases are present in eukaryotic cells?
|
RNA pol I RNA pol II RNA pol III |
|
|
What does RNA pol I do?
|
Responsiblefor ribosomal RNA in the nucleolus
|
|
|
What does RNA pol II do? |
Responsiblefor transcribing mRNA in the nucleus
|
|
|
|
Responsible for tRNA in the nucleus
|
|
|
How do the GTFs assemble on the promoter to form the PIC?
|
1. TFIID assembles over the TATA box 2. TFIIA and TFIIB are recruited 3. TFIIB interacts with the RNA polymerase 4. TFIIF is recruited 5. TFIIE and TFIIH are recruited 6. Promoter melting and helicase activity in the TFIIH forms the open complex. |
|
|
Describe the major events that occur during transcription initiation?
|
1. Helicase activity of the TFIIH separates the template strand at the start site forming an open complex - requires ATP hydrolysis. 2. Pol II begins promoter clearance by transcribing, it is hyperphosphorylated at the CTD. 3. TFIID and TFIIA stay behind. 4. TFIIB, TFIIE and TFIIH are released. 5. TFIIF moves down the template with pol II. |
|
|
What is the composition of TFIIH and what are its roles in transcription? |
TFIIH is a multifunctional complex. 2 Parts - core and CAK module CAK contains on e of the kinases that phosphorylates the CTD of RNAP II. 9-10 subunits > p44, p62, XPD XPB, Cdk7. |
|
|
What types of subunit make up TFIID? What are the functions of these subunits?
|
Central RNA pol II transcription factor. Composed of TATA binding protein (TBP) and TATA binding protein associated factors (TAFs). Trilobular factors. |
|
|
What is the role of XPB?
|
Involved in promoter melting. |
|
|
What do TAFs do?
|
Promote interaction of the TFIID with basal promoters. |
