Fig. 3.

Western blots of protein extracts from wild-type and n-syb mutant heterozygotes probed with anti-n-syb antiserum. The molecular weight size markers are in kilodaltons, and the band corresponding to size of then-syb protein (∼22 kDa) is indicated. Proteins extracts from either 10 heads or 10 bodies (A) or 20 heads (B) from the indicated lines were prepared as described in Material and Methods. A,n-syb protein is enriched in wild-type (wt) heads as compared with the rest of the body (wt body); the starter P-element line, line 34, has wild-type levels of n-syb. All of then-syb mutant heterozygotes have reduced levels ofn-syb protein. B,n-syb^ΔF33-8 produces a slightly higher molecular weight form of n-syb (indicated with anarrow) than wild type. This is most likely attributable to the use of an alternative initiation ATG in intron 1. The higher molecular weight band present in all of the lanes, running at ∼35 kDa, appears to be a protein that cross-reacts with then-syb antiserum because it does not decrease in intensity in the n-syb mutants.