The characteristics of sox gene in Dugesia japonica.

Sox genes play important roles in animal developmental processes, including embryogenesis, neural cell stemness, neurogenesis, sex determination, among others. Here, the full length sox gene in planarian Dugesia japonica, named DjsoxB, was cloned using rapid amplification of cDNA ends (RACE). Phylogenetic analysis demonstrates that DjsoxB is highly conserved evolutionarily in metazoans. Whole-mount in situ hybridization found DjsoxB mRNA to be mainly expressed in the head, intestine and mouth in both sexually mature and immature planarians. Moreover, DjsoxB transcripts were detected in the blastema after amputation and throughout the head regeneration processes. The data from real-time PCR showed that the mRNA expression levels of DjsoxB were distinctly up-regulated from 3 to 7days after amputation. These results suggest that DjsoxB gene might be active in CNS formation and functional recovery during head regeneration, maintenance of adult CNS function and the development of other tissues (e.g. intestine) in D. japonica.