Motoneuron fasciculation and guidance defects in spon-1mutants
| A spon-1 single mutant defects | |||||
| Genotype, temp | n | Ventral cord defasciculation† | Commissure handedness defect‡ | Dorsoventral guidance defect¶ | |
| N2 20° | 43 | 0% | 2.7% (0.2%) | 0% | |
| ju430ts 15° | 42 | 40.5% (6.5%)** | 30.9% (2.9%)** | 9.5% (0.5%) ns | |
| ju430ts 20° | 41 | 31.7% (4.9%)** | 56.1% (8.7%)** | 29.3% (2.4%)** | |
| ju430ts 22.5° | 40 | 17.5% (2.5%)* | 87.5% (15%)** | 40% (4.1%)** | |
| ju430ts 15°-25° upshift | 37 | 16.2% (4.1%)** | 43.2% (4.7%)** | 2.7% (0.2%) ns | |
| B Interaction between spon-1 and unc-71 | |||||
| Genotype | n | Missing 1 or more commissures | Commissure handedness defect | Dorsoventral guidance defect | |
| N2 | 61 | 0% | 0% (0.2%) | 0% | |
| unc-71(ju156) | 45 | 73% | 24% (5%) | 0% (0%) | |
| ju430ts | 45 | 0% | 11% (3%) | 0% (0%) | |
| ju430ts; ju156 | 48 | 100%*** | 44% (10%) | 44% (9%)** | |
| A spon-1 single mutant defects | |||||
| Genotype, temp | n | Ventral cord defasciculation† | Commissure handedness defect‡ | Dorsoventral guidance defect¶ | |
| N2 20° | 43 | 0% | 2.7% (0.2%) | 0% | |
| ju430ts 15° | 42 | 40.5% (6.5%)** | 30.9% (2.9%)** | 9.5% (0.5%) ns | |
| ju430ts 20° | 41 | 31.7% (4.9%)** | 56.1% (8.7%)** | 29.3% (2.4%)** | |
| ju430ts 22.5° | 40 | 17.5% (2.5%)* | 87.5% (15%)** | 40% (4.1%)** | |
| ju430ts 15°-25° upshift | 37 | 16.2% (4.1%)** | 43.2% (4.7%)** | 2.7% (0.2%) ns | |
| B Interaction between spon-1 and unc-71 | |||||
| Genotype | n | Missing 1 or more commissures | Commissure handedness defect | Dorsoventral guidance defect | |
| N2 | 61 | 0% | 0% (0.2%) | 0% | |
| unc-71(ju156) | 45 | 73% | 24% (5%) | 0% (0%) | |
| ju430ts | 45 | 0% | 11% (3%) | 0% (0%) | |
| ju430ts; ju156 | 48 | 100%*** | 44% (10%) | 44% (9%)** | |
D morphology was scored using the Punc-25-GFP (juls76)marker in young adults (A), or in L1 larvae (B); only commissures of DD2-6 were scored in L1s. All defects are scored per animal (n) and per neuron/commissure (or per ventral cord segment for defasciculation). Data in B are all at 20°C. Tests of significance use the Fisher exact test(*P<0.05, **P<0.01, ***P<0.001).
ns, not significant.
Ventral cord defasciculation: the ventral nerve cord was divided into 10 sections between D neuron cell bodies. An animal is scored as defasciculated if two or more segments are defasciculated.
Commissure handedness defect is outgrowth of a commissure on the left side. The two anterior commissures (DD1/VD2) of the left side and most anterior commissure on the right side (VD3) were not scored.
Dorsoventral guidance defect is % animals with >1 commissure that fails to reach dorsal cord. About 8% of D neurons did not extend commissures from the ventral cord. We observed similar defects in A and B type motoneurons (not shown).