siRNA time - (Jan/04/2012 )

Hi I have been trying to get knock down for a few months now, using dharmacon smart pool....i am being told that i am missing knock down because the half life of the protein i'm looking at is 8 hours therefore the RNA half life is much shorter....The protocol suggests 24-48 for RNA analysis & i'm being told 2-3 hours, is this too short?

Binding to RISC stabilizes the guide strand, so if your siRNA is loading then it should be fine for 48 hours. An alternative is to use a more stable knockdown reagent, but a 48 hour knockdown should not be too long for siRNA.