February 14, 2005 at 8:51 pm #381mithParticipant
What is siRNA and RNAi?
February 15, 2005 at 11:28 am #19622
small interfering RNA (siRNA), RNA interference (RNAi) also called RNA silencing
Its the phenomenom by which introduced double stranded RNA has the effect of silencing expression of any genes encoding mRNAs with similar sequences. It’s probably a viral defence mechanism but is useful because you can introduce an siRNA molecule , or siRNA producing vector into a cell and switch off down expression of the genes you wish to study.
In our hands in plants its more of a turn down rather than a switch off, so we were able to study the effects of reduced gene expression when a complete knockout would have been lethal.
Hope this helps
February 15, 2005 at 8:24 pm #19634mithParticipant
Very interesting, where do you work if you don’t mind my asking?
February 16, 2005 at 9:32 am #19646
February 18, 2005 at 4:56 am #196842810712Participant
How does this happen?
It’s probably a viral defence mechanism but is useful because you can introduce an siRNA molecule , or siRNA producing vector into a cell and switch off down expression of the genes you wish to study.
And are you saying that this is antiviral?
February 18, 2005 at 10:09 am #19687
Yep appears to be a cellular antiviral mechanism
http://www.ncbi.nlm.nih.gov/entrez/quer … s=12554663
and reviewed in Trends in Genetics
RNA silencing as a plant immune system against viruses
Trends in Genetics 17:449 (2001)
http://www.sciencedirect.com/science?_o … e9e26026b3
March 27, 2005 at 9:25 am #20889GreenDogParticipant
Maybe it appears to be an antiviral mechanism, but is probably not, is serves a much more basic function in development.
The phenomenon exists in fungi- called quelling, in plants- PTGS, and in C. Elegans.
Two major participants in the system Dicer (dsRNA endonuclease) and RISC (RNA-Induced Silencing Complex), have roles that affect gene expression, and not only virus response uses.
PTGS – Posttranscriptional gene silencing in plants and ‘quelling’ in fungi are plant-based RNAi mechanisms.
May 7, 2005 at 9:16 am #22217yykangParticipant
more and more proofs surport that RNAi is a antiviral mechanism in organism. I think the further study should focus on the application for gene therapy and gene function study.
April 19, 2006 at 8:58 pm #46811TairaKawasakiParticipant
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