Alex Palazzo is an Assistant Professor in the Department of Biochemistry at The University of Toronto.
After the last miRNA post, I was alerted to this paper that appeared in the June 15th edition of Nature:
How did I miss that? The basic story is that eIF6 was co-purified with the RISC complex. To remind you RISC is a protein agglomerate that helps miRNAs downregulate the translation of targeted mRNAs into protein. And eIF6 is not a typical eukaryotic translation initiation factor (eIF) ... in fact this protein acts to inhibit the initiation of protein synthesis. eIF6 accomplishes this by binding to the small subunit of the ribosome and thus preventing the small and large ribosomal subunits from assembling onto the mRNA. Without proper ribosomal assembly at the beginning of the transcript, translation of the messager RNA can never start.
When the authors of the study inhibit the production of eIF6, the ability of a miRNA and the RISC complex to inhibit the translation of a target mRNA was severely impaired.
So here is yet another way that miRNAs and RISC inhibit protein synthesis from targeted mRNAs.
Now the big question is how many other ways will miRNAs inhibit translation?
Comments
.....and soon they gonna FLAG-tag the whole nucleus.....and then the whole cell....and then mother earth. Keep on Tagging !!!
Posted by: Dr Evening | July 4, 2007 9:57 AM
nice comment Dr. Evening
Posted by: sparc | July 4, 2007 12:19 PM
in how many other ways will miRNAs inhibit translation?
Well...anything is possible...one just has to show it...I would suggest to put FLAG tags to any protein involved in RNA biology (which is actually done in the corresponding lab)...purify all those complexes and go with the most sexy one (always Figure 1 in Cell, Nature or Science...check it out)....do some quick biochemical experiments and ask your co-authors to show the physiological role....and yet we have another stunning paper out there and some new model that revolutionizes our understanding of Biology...
FLAG it or leave it
Posted by: Dr Evening | July 5, 2007 6:03 AM
So from your veiled comments I gather that you don't buy the results from this, or other studies, coming out of this group?
Posted by: apalazzo | July 5, 2007 8:45 AM
Well...
This particular paper is quite interesting though the finding that eIF6 binds to the LARGE subunit of the ribosome is rather old. It surely deserves publication. No doubt here. But in my opinion the physilogical relevance is overrated as the paper itself being a full article in Nature. Coming back to your initial question...there is for sure quite a lot of ways in which miRNAs will act on translation.....and with the efforts made so far in the field it does not come as a too big surprise. In general, I am bored reading these FLAG papers one being a blueprint for the other......its a bad machine...totally automatic. There is just no esprit......a mere delivery of data. What was the meaning of PhD again?
Well then....get automatic
Posted by: Dr Evening | July 5, 2007 12:35 PM