please recommend some common miRNA expression vectors - (Oct/22/2007 )

could you please recommend some common miRNA expression vectors that I can easily find with two cloning sites? many thanks. I knew people use the EcoI site of pCDNA3.1, but I prefer two cloning sites, can I use the two cloning sites of this plasmid to clone my miRNA in ? how can I guarantee it express miRNA instead of protein? many thanks.with two cloning sites? many thanks.

Any shRNA construct vector will do such as pSilencer™ 4.1-CMV Expression Vector from Ambion. You just synthesize two complementary oligos based on the precursor miRNA sequence and insert them into the vector after annealing.

Edit: inserting just the pre-miRNA sequence may not working, some flanking sequences are needed as discussed here: http://www.ambion.com/techlib/tn/116/21.html

If the miRNA sequence doesn't have ORF, there will be no translation.