participates in the establishment of left-right asymmetry during amphioxus development by controlling expression.

Correct patterning of left-right (LR) asymmetry is essential during the embryonic development of bilaterians. Hedgehog (Hh) signaling is known to play a role in LR asymmetry development of mouse, chicken and sea urchin embryos by regulating expression. In this study, we report a novel regulatory mechanism for in LR asymmetry development of amphioxus embryos. Our results revealed that embryos abolish () transcription, with bilaterally symmetric expression of , and In consequence, mutants duplicated left-side structures and lost right-side characters, displaying an abnormal bilaterally symmetric body plan. These LR defects in morphology and gene expression could be rescued by mRNA injection. Our results indicate that participates in amphioxus LR patterning by controlling gene expression. Curiously, however, upregulation of Hh signaling failed to alter the expression pattern or LR morphology in amphioxus embryos, indicating that Hh might not provide an asymmetric cue for expression. In addition, is required for mouth opening in amphioxus, hinting at a homologous relationship between amphioxus and vertebrate mouth development.