Fig. 3. Identification of the DMBS mutations. (A) The genomic structure at the DMBS locus. The exon/intron structure is shown with columns and lines under the genomic map. The coding and untranslated regions are indicated as red and blue columns, respectively. The DMBS-L-specific exon is represented by a yellow column. The sites of the P-element insertions are indicated above the map. (B) Reduction in the amounts of the DMBS proteins in DMBS mutants. Protein blots were probed with either an anti-DMBS-C1 antibody (upper panel) or an anti-Pnut antibody (lower panel). Extracts were prepared from late third instar larvae of the following genotypes; wild type (lane 1), Df(3L)th117/DMBS^P2r31 (lane 2), DMBS^E1/DMBS^P2r31 (lane 3), and DMBS^P1/DMBS^P2r31 (lane 4). Arrows indicate the positions of DMBS bands. (C) Increase of phospho-MRLC in DMBS mutant larvae. The extracts were prepared as described (Winter et al., 2001) from the larvae as in B, except for lane 5 for which sqh^AX3; GFP-Sqh larvae were used. Protein blots were probed with an anti-phospho-MRLC antibody (upper panel) or an anti-Sqh antibody (lower panel). The band corresponding to the GFP-Sqh fusion protein is not included. (D) Reduction in the amounts of DMBS proteins in the DMBS mutant females. Protein blots were probed with either an anti-DMBS-C1 antibody (upper panel) or an anti-Pnut antibody (lower panel). The extracts were made from adult females of the following genotypes; wild type (lane 1), Df(3L)th117/DMBS^P2 (lane 2), DMBS^E1/DMBS^P2 (lane 3), and DMBS^P1/DMBS^P2 (lane 4). Arrows indicate the positions of the DMBS bands.