Fig. 3. Mutations in UAS-brk^A438, which originally contained a wild-type brk transgene. (A) Wild-type adult wing. (B) Misexpression of wild-type A438 results in a dramatically reduced wing. (C-G) Misexpression of mutated forms of A438, however, results in larger wings: from completely wild-type in the case of A438-53, indicating a complete loss of activity, to small in the case of A438-S4 and A438-C, indicating significant, but less than wild-type, activity. Wings produced with A438-D44 and A438-F2 are almost wild type in size, but have venation defects indicating that some activity still remains.