Figure 5.—

Western blot of Sxl proteins from wild-type and Sxl mutant D. virilis male heads and testes. No Sxl proteins were found in extracts of adult males hemizygous for the predicted null allele, vSxl^f1 (vF1). Sxl proteins from males hemizygous for the intragenic deletion allele vSxl^f2/Y (vF2) matched those from wild-type males (vWT) in mobility, but seemed somewhat more abundant. Note the difference between testes and heads with respect to the male Sxl proteins generated. The doublet for Sxl is likely due to the use of alternative exon 5 3′-splice sites (see Figure 6) (Bopp et al. 1991).