Gene Regulation II Flashcards
What features are common to transcription factors?
Acidic and basic amino acids (H bond with DNA) within regions of the protein - specific sequences and 3-D structure
What are 2 examples of transcription factor structures?
Zinc finger
Helix-turn-helix
What is the DNA sequence that is recognized by NFkB?
GGGGACTTTCCC
What type of bonds are important in DNA/protein interactions?
Hydrogen bonds
What are the 4 transcription factor structural domains?
Helix-turn-helix
Zinc finger
Leucine zippers
Activation domains
What structural shape do steroid hormone receptors have?
Zinc finger
What are leucine zippers involved in?
Protein/protein interactions
What do activation domains interact with?
RNA polymerase
Highly acidic OR glutamine-rich regions
What shape do homeodomain proteins take?
Helix-turn-helix
What are the 3 homeodomain proteins mentioned?
Hox
Msx-1
Barx-1
What are the 4 steroid hormone receptors mentioned? What shape do their domains take?
ER, PR, AR, GCR
Zinc finger
What is the one example given of a receptor that is in leucine zipper shape?
AP-1
What is the procedure to detect DNA/protein interactions in a gel mobility shift assay?
Nuclear proteins are extracted and incubated with a specific, tagged DNA consensus sequence
DNA/protein mixture is loaded into a non-denaturing polyacrylamide gel
DNA migrates quickly
DNA+protein migrates more slowly
What are the 8 steps of binding for activation complexes, as well as RNA polymerase (Pol II)?
- Activators
- Chromatin modifiers
- Coactivator complex (mediator)
- TATA binding protein (TBP) & TFIIB
- Individual basal transcription factors
- Pol II binds to Inr region
- Carboxyl terminus of Pol II complexes with mediator
- TFIIH phosphorylates Pol II & initiates transcription
What are two other names for micro-RNAs?
Small temporal RNA (stRNA)
Small interfering RNA (siRNA)
What do micro-RNAs do?
Mediate the silencing of many genes
What do micro-RNAs interact with? In which direction?
mRNA
Usually in 3’ UTR
What 2 things do micro-RNAs cause?
mRNA degradation
OR
Inhibition of translation
Some miRNAs are involved in formation of what?
Heterochromatin
What is dicer?
An enzyme that cleaves double stranded RNA
What happens to RNA after dicer cleaves it?
Strands will then pair with an mRNA
