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about siRNA and shRNA - RNAi Vector (Jan/26/2006 )

Hi. All,

I want to do some studies on RNAi, but don't know the efficiency of which one is more perfect, siRNA or shRNA vector. And also, if can I use shRNA vector directly to knock-down the target gene? that is to say, Need I select a better siRNA first? and then constructe shRNA vector?

Thanks al lot,



these names are related to same process.
As you may know, siRNA is a double strand RNA molecule 17-23bp long and holds a 3' overhang.

ShRNA : in vectors, the sequence transcribed is as : sense_loop_antisense. After transcription, the complementarity drive an auto folding of the molecule, resulting in an harpin. This hairpin is then recognized by Dicer and goes well in the RNAi pathway.


I would suggest that you first use synthetic siRNA to find out which targets work the best, then if you want to achieve long-term knockdown, construct the screened siRNA into a shRNA vector.