Lentiviral Transduction of miRNA Precursors

The lentiviral vectors (System Biosciences) encoding miR-16 and other miRNAs were packaged and used to infect cell lines KP1-KP3, as described previously (Sachdeva et al., 2012 (link)). Briefly, pre-miR-16, pre-miR-146, pre-miR-223 and pre-miR-342 sequences were first PCR amplified using mouse genomic DNA as a template and Platinum Taq polymerase enzyme (Invitrogen) with corresponding specific primers. Primer sequences are shown in supplementary material Table S2. The amplified fragment was then cloned into a lentiviral vector (pCDH-CMV-MCS-EF1-copGFP from System Biosciences, Mountain View, CA) at EcoRI and NotI sites using the Choo-Choo cloning kit per the manufacturer's protocol (MCLAB, San Francisco, CA). The lentiviral vector was packaged using the pPACKH1 Lentivector Packaging Kit (Systems Biosciences, Mountain View, CA).