Figure 1.

(A) Schematic drawing of the Atm protein based on ref. 14. Shown are the leucine zipper (LZ) and PI-3 kinase (PI3K) domains. An arrow marks the approximate location where the mutation described in the work was introduced. (B) Schematic drawing of the wild-type atm gene (WT), the targeting construct (V), and the mutated atm allele (KO). RI, EcoRI; B, BamHI. Note that the Neo and atm genes are transcribed in opposite orientations. Use of the internal probe A in conjunction with EcoRI digestion in DNA blot analysis results in bands of 6.5 kb and 8.3 kb for the wild-type and mutated alleles, respectively.