Fig. 7. ISNb and ISN phenotypes in Ptp52F and double mutants. Dissected late stage 16 embryos stained with mAb 1D4. (A) Ptp52F^18.3. The ISNb has a normal appearance. Muscles are labeled. (B) Ptp10D¹, Ptp52F^8.10.3.. The left ISNb has stalled at the proximal edge of muscle 13 (arrow) without making a synaptic branch. The right ISNb is also truncated. The distal portion of the ISN is shown in C-F. Terminal arbors are indicated by arrowheads in C,E; the large tracheal branch just distal to the second branchpoint is indicated by asterisks in C-F. (C) Ptp52F^8.10.3. (D) Ptp69D¹/Df(3L)8ex25. The ISN has a normal appearance in these single mutants. (E) Ptp10D¹, Ptp52F^8.10.3.. Terminal arbors are reduced in this double mutant. (F) Ptp52F^8.10.3, Ptp69D¹/Df(3L)8ex25. ISNs stall at the second branchpoint position (arrow), proximal to the tracheal branch.