The miR-15b/16-2 hairpin spans 430 bp. To generate the miR-15b/16-2 KO targeting vector, DNA fragments flanking miRNAs, with a NotI-BamHI fragment (3.4 kb) as the 5 arm and a HindIII-EcoRI fragment (1.3 kb) as the 3 arm, were isolated from a 129/Sv genomic library and subcloned into a pflox vector. Two selectable markers are incorporated into this vector. The neomycin resistance gene (neo) is flanked by loxP sites and located between the two arms. (J:226920)