, which was originally discovered in the salivary glands of the Mexican leech , was newly isolated from . To confirm the temporal expression of during embryogenesis, we carried out semi-quantitative RT-PCR. was uniquely expressed at stage 4 of the cleavage and was strongly expressed in the late stages of organogenesis, as were other members. In order to confirm the spatial expression of , we performed fluorescence in situ hybridization in the late stages of organogenesis. The expression of each in the proboscis showed a similar pattern and varied in expression in the body. In addition, the spatial expression of orthologs in different leeches showed the possibility of different function across leech species. was expressed in the same region as , which is a known mediator of signal transduction pathway. Hau-antistasin1 is probably a downstream target of Hedgehog signaling, involved in segment polarity signal pathway.