Redundancy and compensation in axon guidance: genetic analysis of the Drosophila Ptp10D/Ptp4E receptor tyrosine phosphatase subfamily

Table 1 CNS axon phenotypes in Rptp double and triple mutant embryos

CNS longitudinal axons were scored by counting the number of longitudinal tracts in each hemisegment at the midpoint between commissures (visualized by residual 1D4 staining at stage 17). In wild-type embryos, there are three fascicles per hemisegment. n, total number of hemisegments (T2–A6) scored at stage 17. Two: hemisegments with only two longitudinal tracts where the outer bundle is missing or is fused to the medial fascicle. One/none: hemisegments with only one or no longitudinal tracts. Cross-over: segments where axons abnormally cross the midline. *Expression of UAS-4E-GFP in neurons using the elav-GAL4 driver produces incomplete rescue (from 30% to 7%, versus 1–2% in single mutants). However, the statistical difference between Ptp4E¹ Ptp10D¹ and Ptp4E¹ Ptp10D¹; UAS-4E-GFP/elav was highly significant (p < 0.0001, Chi-square test), indicating that pan-neural expression of Ptp4E rescues. ^† Statistical differences between Ptp4E¹ Ptp10D¹ and each of the single mutants were also significant (p < 0.0001, Chi-square test).

ISSN: 1749-8104