Fig. 2. ptpmeg is required for mushroom body (MB) axon patterning. (A) Diagram of the mushroom body (MB) with the neurons labeled in bold type. The locations of , ', ß, and ß' lobes are indicated. (B,C) MB neurons visualized with OK107-Gal4;UAS-mCD8:GFP. In normal adults (B), dorsally projecting and ' lobes are of similar thickness as medially projecting ß and ß' lobes. ß and ß' lobes project towards the midline but do not touch or cross it. In ptpmeg mutants (C), and ' lobes are reduced, appearing thin and/or short (arrow), and ß and ß' lobes overgrow, touching the midline or fusing with the contralateral MB (bracket). (D-I) and ß lobe axons from adult left brain hemispheres labeled with anti-Fasciclin II. E-G highlight the lobe defects of ptpmeg mutants, including short (E, arrow), thin (F, arrow), and missing (G, asterisk) lobes. (H) lobe reduction in ptpmeg mutants is rescued by expression of Ptpmeg in neurons using Elav-Gal4. (I) Animals with large clones of homozygous ptpmeg¹ mutant MB tissue (marked in green) in otherwise heterozygous animals do not exhibit MB defects. (J) Normal spacing of ß lobe termini near midline. (K,L) ß lobes touch midline (K) or fuse with contralateral ß lobe (L) in ptpmeg mutants. (M) ß lobe defects in ptpmeg mutants are rescued by expression of wild-type Ptpmeg in neurons using Elav-Gal4. The midline is marked with arrowhead in J-M.