How does the shape of mRNA change during translation?
Jon Moulton
Tuesday, 04 September 2007 22:57 UTC
This is a request for help regarding the conformation of mRNA during translation.
I am working on an animation illustrating gene expression. I am hoping to represent the RNA during translation as accurately as possible (while still clearly communicating the main ideas). Is the following sequence correct?
During cap-dependent translation initiation, poly-A associates through poly-A binding proteins (PABP) with eukaryotic initiation factor 4G (eIF4G) and some other initiation factors.
http://www.jbc.org/cgi/content/abstract/282/35/25247
This makes the mRNA form a loop.
Once the small subunit moves toward the start codon, it takes along eIF4G (I gather from the figure on this page):
http://en.wikipedia.org/wiki/Eukaryotic_translation
This implies that the circularized mRNA is forming a lariat-like structure, with the single stem of the lariat getting longer as the small subunit moves farther from the 5’-cap of the mRNA.
What happens when the large ribosomal subunit binds? Based on the wikipedia illustration cited above, I would expect that eIF4G falls off the RNA and so the lariat opens, recircularizing later for the next round of translation.
The sequence:
Linear mRNA
(PABP binds eIF4G)
Circular mRNA
(initiation complex scans for start codon)
Lariat mRNA
(large subunit of ribosome binds)
Linear mRNA
Thanks for any suggestions or pointers toward a clearer story!
- Jon
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Replies
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Hey! just about a month I made a scheme for a review, now the review is revision, probably it would be release at the beginnig of the next year. I read a lot about the protein interactions, so I think is a really good scheme of translation. I conact you when the review is out.
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