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20 Cards in this Set
- Front
- Back
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what kind of of rna edits are there?
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deletions, insertions, base changes
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how are the edits facilitated?
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enzymes recognize specific RNA sequences
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what can happen to adenines?
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get deaminated, turn into a inosine, recognized as a G instead
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what deaminates?
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ADAR
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Where are inosines often found?
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in tRNA
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which cells have the most editing?
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neuronal cells
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Describe AU-rich elements:
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typically at 3' UTR, often multiple copies/mRNA, recognized by specific proteins, stimulate mRNA deadenylation
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What usually has AU-rich signals?
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immune responses
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3 types of degradation
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Decapping- get rid of the 5’ cap
Deadenlyation- eat up the poly a, then exosomes chew that shit up Endonucleolytic pathway- cut it in half with a protein(RNAi pathway) |
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describe an exon junction model
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• Right after splicing, things called the exon junction complex binds to where the exons are ligated together.
o Splicosome helps deposit these • First translation will remove the EJC, knocks the EJC off as its translated. In a nonsense mutation, there is a premature stop codon thus leaving EJC is. EJC recruits deadenylase, and the mRNA is degraded. • Problem: when stop codon is in the last codon, there is no longer nonsense mediated decay. |
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What happens in global translational control? example?
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Repression of all translation, ex. TOR
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what is a CPE?
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sequence in mRNA, binds to CPEB, which recruits maskin
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How is translation inhibited?
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without phosphorylation cpeb binds to cpeb, which binds maskin, which binds to the initation factor, not allowing translation
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how do you get translation to be allowed?
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kinases phosphorylate CPEB, which now cant bind to maskin, leads to start of translation. also poly adenylation starts
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What happens in low iron conditions?
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body wants more
ferritin off, transferrin receptor on |
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what happens in high iron conditions?
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prevent toxic levels, transferrin receptor expression off
ferritin on |
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what's an IRE-BP?
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iron response element binding protein, can only bind when iron is not there
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How is ferritin regulated?
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if there is high iron, ire-bp will not bind to the ferritin gene, and translation of ferritin will occur,
if there is low iron, IREs in ferritin will be bound and not translated |
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What is a transferrin receptor and what does it do? how is it regulated?
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transferrin receptors bind transferrin which assists in iron transport in the body.
When IRE-bp is inactive AU-rich regions are exposed, and degradation will occur, but when IRE-bp is active, it will not degrade |
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How would you test localization of mRNA?
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try different UTR's
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