siRNA overhangs - (Jun/23/2010 )

Hiya,

Ive just started trasfecting cells for the first time.

This may seem a very basic question but... can somebody explain to me why the siRNA duplex has to have overhang ends (usually dTdT)?

Cheers!

3'-overhangs can facilitate RISC loading. siRNA duplexes without overhangs work equally well. definitely, duplexes with 5' overhangs do not work.

To add to the previous post my experience with the literature says that sequence of the dinucleotide overhang (dt,dt or dA,dA etc) isnt important for siRNA activity just that its there on the 3' ends, however most studies use dTdT which has become convention. GG overhangs are also avoidable because they are more reactive than the others