Mice carrying the Mirc1tm1Tyj (2frt/2lox) allele were crossed to mice expressing an ACTB-cre transgene to excise the floxed cluster, including Mir17, Mir18a, Mir19a, Mir20a, Mir19b-1, and Mir92-1, but leaving the Frt-flanked neomycin cassette. (J:134861)