Gt(ROSA)26Sor^{tm4(RNAi:Gsk3a,Gsk3b)Rkuhn}

Recombinase mediated cassette exchange (RMCE) was used to generate an allele where upon expression of Cre recombinase knockdown RNAis are generated to both Gsk3a and Gsk3b. Short hairpin RNAs were designed with a loxP-flanked stop cassette in the loop portion of the RNAi between the sense and anti-sense sequences. The RNAis were both put under the control of separate human U6 promoters and the entire cassette was placed downstream of a splice acceptor and a frt-flanked neomycin resistance gene. RMCE was then performed on ES cells containing the Gt(ROSA)26tm1Rkuhn allele. Upon expression of cre recombinase, protein expression of Gsk3a and Gsk3b were reduced by 84% and 52%, respectively. (J:133340)