Figure 1.

Transgene expression in ko^tg mice. Total cell lysates from B220⁺ spleen cells and v-abl-transformed pre-B cells were subjected to Western blot analysis and probed with an anti-Btk polyclonal antibody. Transgene-derived Btk protein was quantified by comparison with a 1:4 dilution of wild-type cell lysates into Btk-deficient cell lysates. Equal loading of samples was confirmed by Coomassie blue staining of the bottom portion of the gel and reprobing the blots with an anti-lyn polyclonal antibody.