Characterization of AID transgenic mice. A Schematic representation of the transgenic AID constructs (fragments are not depicted in scale). The location of the PCR primers a and b used for genotyping is shown. B PCR of 63 pups (18 are shown here) revealed that 9 of them (three are shown here, number 1, 4 and 15) had integrated the AID transgene. In the same PCR tube, β-actin was amplified to control for genomic DNA content. Vec. represents the control PCR performed using the transgenic vector as a template. C Real Time PCR showing the expression levels of the AID transgene in different lines. D Immunoprecipitation and western blot was conducted from a brain hemisphere of AIDtg and littermate (Con) mice. Mice lines that expressed the AID protein at the mRNA level, and had a detectable band at the western blot analysis were selected for further studies.