RNA Regulation Flashcards
What are the two classes of RNA-RNA interaction?
Intramolecular RNA element
sRNA
Intramolecular RNA elements do what?
Act in cis only
Regulate transcription and translation
RNA thermosensors
Riboswitches
sRNAs do what?
Signaling cascades
Regulate transcription, RNA stability, and translation
Act in cis or trans
Cis-sRNA
Specific to one gene
Hides SD or shifts hairpin
Cis-antisenseRNA
Regulates transcription (dual promoters), stability (dsRNA unstable), translation (hide SD)
Trans-sRNA
Global interference
Hides or frees SD
What’s the structure of a trans-sRNA?
Seed sequence
Hairpin with poly U
Hfq site
What does Hfq do?
It’s an RNA chaperone required for most sRNA-mRNA interactions
Increases local concentrations of RNAs (RNA - and Hfq +)
6 subunits to bind 6 RNA
Helps recruit RNase E to degrade mRNA
How does Hfq help recruit RNase E?
Increases abundance and length of RNA = more Hfq binding = more dsRNA formation
Hfq stalls translation and is bulky so it blocks ribosome
Why are transcription and translation coupled?
To prevent exposure of ssRNA
SRNAs control what integral components of transcriptional circuits?
Starvation response
Membrane trafficking
Cofactor transport
Can you computation the mRNA targets of sRNAs?
No, the seed sequence is too short to predict interactions
How do you ID mRNA targets of sRNAs?
Look for reduced gene expression
Use a reporter gene to measure expression levels
RNA thermosensors
Specific to one gene
Heat melts hairpin
Riboswitches
Aptamer formation (structural RNA sequence that binds to a small molecule or metabolite)
Binding triggers a change in transcriptional or translational regualtion
