is microRNA degraded with target? - is there any known pathway for miR degradation? (Feb/03/2008 )

Has anyone seen any evidence to suggest that microRNA is degraded with its target- my feeling is in most cases not, but has anyone really investigated this?
futhermore, is there any known degradation pathway? it seems like the cell would want to be able to specifically down regulate miR, but I haven't seen any literature to this effect. I would really appreciate your thoughts or any references you might know of. I think it is an interesting idea, but I also don't really know what experiment you would do to look at miR degradation- any thoughts on this?
thanks!

Good question ... I'd like to know that either. In plants no degradation pathway is described. I haven't even red an hypothesis, and I have none at the moment.

I agree that the cell should want to have a pathway for degrading miRNAs, but I haven't seen any papers on it either. As an experiment, perhaps you could transfect cells with an siRNA that is labeled (radioactive, DIG etc?) and track what happens to it? (i.e. half life, localization etc)? If you set up a system to track degradation of the siRNA you could then maybe perform an RNAi screen to find proteins that are required for the process, or maybe just start with knicking out the known miRNA biogenesis machinery?

Good luck, I think that this would be an interesting and important study!