|Budget Amount *help
¥3,600,000 (Direct Cost : ¥3,600,000)
Fiscal Year 2003 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 2002 : ¥2,200,000 (Direct Cost : ¥2,200,000)
Segmentation along the antero-posterior axis of the body is seen in a wide range of species in animal kingdom, including vertebrates, arthropods, and annelids. It remains unknown whether the mechanisms underlying the body segmentation are shared by these animals, or whether the segmental pattern emerged independently during animal evolution. Whereas the molecular mechanisms by which the segmentation is regulated have well been studied in Drosophila and vertebrates, those for annelids remain undetermined. We reasoned that the study of segmentation in annelids will provide valuable information concerning how the animals evolved their body pattern during evolution. We used Enchytraeus japonensis, a small worm recently found in Japan, which is endowed with a powerful capability of regeneration, to understand how their segmented body is established during regenerative processes. We identified cDNAs that were specifically expressed during the regeneration by subtractive hybridization technique, and also by in situ hybridization in histological sections. In addition, we, examined expression of genes known to be involved in the segmentation in Drosophila or vertebrates, such as Delta, Notch, and Wingless (Wnt). We have not found a segmented pattern expressed by these genes, implying that the segmentation in worms is regulated by distinct mechanisms from those in flies and vertebrates.