How to construct miRNA expression vector - (Sep/20/2008 )

Dear everyone,I want a eucaryotic miRNA expression vector that can replicate with the cell division,so that the each daughter cell can get the copies of this vector.can you give me suggest where to buy it or how to construct it (such as use what kinds of origin and promoter)
many thanks!

We use pCDNA3.1 vector to expression miRNA. It works very well.

To construct miRNA expression vector, we PCR amplify pre-miR sequence from genomic DNA using primers that have incorporated endonuclease restriction sites. The amplified region should not just be the precursor sequence, but also include ~150 bp flanking sequence at both ends, so the insert size is ~400 bp.