interaction of viral protein with RNAi machinery - (Apr/08/2008 )

If I'm doing a test by transfecting viral proteins in human liver cells to see if some of these proteins interact with the host cell RNAi machinery. What should I expect? An upregulation of mature miRNA's or a downregulation of the mature miRNAs (expecting the viral protein has an effect).

It could be that the viral protein interacts with Dicer, en that no mature miRNAs can't be form so it will give a downregulation
But if it interacts for example with the RISC complex than there will probably be some mature miRNA's ? -> upregulation

Does anyone has a suggestion?

How about this possibility -- the viral protein interacts with the loop region of a pre-miRNA, inhibiting Dicer processing of that specific miRNA. This would be similar to the let-7 miRNA and lin-28 protein interaction.

See:
www.sciencexpress.org / 21 February 2008 / Page 1 / 10.1126/science.1154040
Selective Blockade of MicroRNA Processing by Lin-28
Srinivas R. Viswanathan, George Q. Daley, Richard I. Gregory