Figure 1.

ATM is expressed in adult brain. (A) Protein (100 μg) obtained from SDS extracts of wild-type (lane 1) and Atm−/− mouse (lane 2) cerebella was subjected to electrophoresis on a 5–15% linear acrylamide gradient gel, followed by immunoblotting with AM9. Note reactivity with the high-molecular-mass (≈350 kDa) ATM protein. Additional immunoreactivity was observed against a ≈55-kDa protein that is likely to be a proteolytic fragment of ATM, because its presence is confined to the extract from wild-type brain. (B) Extracts used in A (5 μg) were subjected to analysis with a calbindin antibody (Chemicon) to confirm equal protein loading.