Sirt1^tm1Ygu

A floxed neomycin cassette was inserted just upstream of exon 4 and a third loxP site was inserted just downstream. The floxed mutation does not affect the protein expression of the targeted gene in MEF's or mammary tissue from homozygotes. When bred to mice that express Cre recombinase, the resulting offspring will have exon 4 (encoding a conserved Sir2 motif) deleted in the cre-expressing tissue(s). (J:85542, J:121948)