| | Re: What would a western blot with siRNA knockdown show?
There will be a time lag between siRNA treatment and good knockdown. The siRNA will prevent most of the new translation, but preexisting protein will turn over at its usual rate. For some proteins, like many transcription factors, the turnover will be fairly rapid so you can see a good signal decrease within 24 hours. For others, like some structural proteins, the turnover might take several days to detectably decrease the signal on a Western.