Mutations in the Spliceosome Component and Overexpression of Suppress Axon Guidance Defects of Mutants in .

During nervous system development, axons must navigate to specific target areas. In , the cadherin CDH-4 is required for ventral nerve cord axonal navigation, and dorsal nerve cord fasciculation. How CDH-4 mediates axon navigation and fasciculation is currently unknown. To identify genes acting together with , we isolated mutants suppressing the axon guidance defects of mutants. These suppressors showed partial suppression of axonal defects in the dorsal and ventral nerve cords seen in mutants. We identified one suppressor gene, , which encodes a component of the spliceosome. Complete loss-of-function alleles of are lethal, suggesting that the mutation isolated in our suppressor screen is a partial loss-of-function allele. A previous study found that RNAi-induced suppression of leads to changes in the expression of several 100 genes including the cadherin . We found that overexpression of mimics the suppression seen in mutants, suggesting that CDH-5 can partially compensate for the loss of CDH-4.