2. Dazl shRNA construct design Dann C T et al. PNAS 2006;103:11246-11251 ©2006 by National Academy of Sciences

3. Transgene expression and DAZL knockdown Dann C T et al. PNAS 2006;103:11246-11251 ©2006 by National Academy of Sciences

5. Analysis of Dazl-shRNA phenotype Dann C T et al. PNAS 2006;103:11246-11251 ©2006 by National Academy of Sciences

6. Reverse genetics in the rat: Advantages to using in vivo RNAi over traditional knock-out methods Because of the small size of the sequences encoding shRNAs, these sequences can be cloned in lentiviral vectors Production of transgenic founders with lentivirus is easy and efficient In vivo RNAi allows to generate animals with different degrees of gene deficiency. An allelic series of hypomorphs is often more informative for modeling human disease phenotypes Conditional in vivo RNAi approach is now feasable in the rat using tissue specific promoters (RNA polymerase II promoters) driving the expression of shRNAs (embedded in microRNAs)