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8 Cards in this Set
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Export of mRNA from the nucleus |
- multiple polymerases transcribing mRNA from DNA - hnRNPs bind to mRNA --> mRNP (mRNA never naked in vivo) -Importin/exportin reacts with nucleoporin - mRNP + NXF1/NXT1 react with nucleoporin to be exported. - 5' end goes through the pore first and immediately gets covered by ribosomes once entering cytoplasm |
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Quality control of export 1: is RNA spliced |
1. make sure RNA are spliced -NXT1/NXF1 binds to REF and other protein markers of splicing.
-in cytoplasm NXT1/NXF1 quickyly falls off and requires to be imported back to nucleus
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NXF1/NXT1 |
Nuclear RNA export factor 1/NTF2-related export protein 1
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Quality control of export 2: polyA tail right length? |
-Sky1 kinase phosphorylates Npl3 -Sky1 is responsible for concentration gradient of Npl3 and NXF1/NXT1 from nucleus to cytosol. -phosphorylated Npl3 binds to mRNA preventing NXF1/NXT1 from binding. -Glc7 phosphatase dephosphorylate Npl3 once polyA added. |
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nuclear pore |
-composed of 100 proteins -nuclear basket in nucleus side
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Nucleoporin |
-a meshnetwork(net) composed of a mix of hydrophilic and hydrophobic AA blocking the nuclear pore. -FG-repeat: phenylalanine/glycine --> Hydrophobic AA -Importin/Exportin can go through because they also have FG repeats. |
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Nup98 experiment |
Nup98 a type of nucleoporin - Anti-Nup98 to deplete it. -required for import of MBP-GFP fused to importin. - required for excluding protein bigger than 40 kDa. |
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Purified Nup98 cohesion test |
Purified Nup98 FG domain -forms a gel -mutate FG to serine --> liquid
permeability of FG Nup98 -without importin --> no transport -with importin --> can go through |
