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41 Cards in this Set
- Front
- Back
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Why is RNA degraded? |
damaged mRNA incorrectly transcribed/processed mRNA control gene expression |
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Where is casein mRNA expressed? |
Mammary Gland |
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Increase in mRNA is stimulated by what? |
Prolactin |
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How fast is the increase in mRNA compared to txn? |
about 70 fold : about 2 fold |
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How is the half life because of this? |
It increase dramatically about 40fold in response to prolactin |
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How does the Poly(A) tail change? |
its length is increased |
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What else aids stabilisation? |
3' UTR of RNA binds proteins |
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How can the closed loop be degraded? |
it must be broken then endonuclease can gain access |
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Phase I: What are the 3 key enzymes that initiate breakdown? |
Decapping Endonuclease Deadenylases |
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What are the decaying enzymes and how do they affect the mRNA |
DCP 1/2 removing the cap means its no longer circular |
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What are the endoculeases ? And what is their role? |
Argonaute Swt1 Smg they string the nucleotides together |
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What are the Deadenylases ? And what is their role? |
Ccr/Not complex nibbles at the PolyA tail |
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Phase II: What is removed first the cap or tail? |
PolyA tail |
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What are the two exonucleases? |
5' - 3' and 3' - 5' |
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what is the exosome? |
the main 3' - 5' exonuclease |
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what is the exosome structure ? |
2x nucleases = RRP6 and RRP44 core/other subunits function in RNA binding and unwinding |
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What is XRNI and what role does it have? |
5' - 3' exonuclease RNA turnover and processing Txn termination Functions after decapping mRNA |
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In deadenyltation-dependent decay, what chews of the polyA tail? |
CCR/NOT |
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What part of the 5'-3' strand is involved in decapping? |
DCP2 + DCP1 |
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What influences deadenylation-dependent decay? |
ARE nonsense codon C-fos major coding determinant miRNA recognition site miRNA --> silencing |
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What is Rps28B? |
RNA binding protein |
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What causes it to bind to its own mRNA at specific site? |
too much protein |
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What enzyme activates recapping enzymes? |
Edc3 |
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NMD = ? |
Nonsense-mediated Decay |
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PTCs = ? |
Premature Stop Codons |
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How far from a junction does PTCs have to be for NMD to detect? |
more than 55 nucleotides |
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What is the Exon Junction Complex (EJC)? |
the signature left behind after splicing (upstream junction 20-24nt 5') to facilitate mRNA export |
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First round of translation a.k.a ? |
Pioneer round of translation |
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What proteins are recruited to interact with RNA degradation machinery once the ribosome reaches PTC and stops ? |
UPF |
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Whats is RISC ? |
RNA induced silencing complex |
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What is siRNA? and how does it function? |
21 -23 nucleotide RNA perfectly complementary viral defence mechanism leads to degradation of target RNA |
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What is miRNA? and how does it function? |
21-23 nucleotide RNA imperfect complementation key gene regulation mechanism leads to block in translation |
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Name of the enzyme that cuts hairpins out of pri-miRNA transcript? |
DROSHA |
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What exports pre-miRNA from the nucleus? |
EXPORTINS |
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What does DICER do? |
chews off hairpin loop |
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Which duplex binds ARGONAUGTE protein? |
siRNA duplex --> mRNA cleavage |
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Which duplex is involved in asymmetric RISC assembly? |
miRNA |
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Where is the binding site of Argonaute ? |
downstream of ORF |
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What activity does Argonaute not have ? |
endonuclease |
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How does 3' UTR length change during embryonic? |
It gets longer which opens up possibility of finer regulation of how they're used |
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When do 3' UTRS get shorter? |
mRNAs in proliferating cells so they're |
