Mutation screening by PTT. Upper panel, schematic representation of the ATM protein with its presently known domains. LZ: putative leucine zipper domain, Abl: Abl-binding region, PI3K: phospho-inositol 3 kinase family domain. The seven regions analyzed by PTT are shown in relation to the ATM protein. A scale is shown in aa. Lower panel, PTT analysis of the three regions showing abnormal patterns. CTL-T: T-PLL sample showing a normal pattern. CTL-EBV: corresponding EBV-transformed cell line sample. Big-T, Bat-T, Dia-T, Bul-T: T-PLL samples showing abnormal patterns. Big-EBV, Dia-EBV, Bul-EBV: corresponding EBV-transformed cell line samples. Dashes indicate wild-type full-length products and arrows indicate abnormal bands.