BmRobo2/3 is required for axon guidance in the silkworm Bombyx mori

- Bmrobo2/3, a homologue of robo gene is first identified from the silkworm.
- Bmrobo2/3 is expressed in the brain, ganglion and neuropil of the silkworm.
- BmRobo2/3 plays an important role in the longitudinal pathway formation in the silkworm.

Axon guidance is critical for proper wiring of the nervous system. During the neural development, the axon guidance molecules play a key role and direct axons to choose the correct way to reach the target. Robo, as the receptor of axon guidance molecule Slit, is evolutionarily conserved from planarians to humans. However, the function of Robo in the silkworm, Bombyx mori, remained unknown. In this study, we cloned robo2/3 from B. mori (Bmrobo2/3), a homologue of robo2/3 in Tribolium castaneum. Moreover, BmRobo2/3 was localized in the neuropil, and RNAi-mediated knockdown of Bmrobo2/3 resulted in the longitudinal connectives forming closer to the midline. These data demonstrate that BmRobo2/3 is required for axon guidance in the silkworm.