Eight genes expression patterns during visual system regeneration in Dugesia japonica.

Dugesia japonica has become the suitable model system for studying the visual system molecular developmental processes because of their simple structure and high regenerative capacity. To further dissect the molecular events of genetic network controlling the visual system regeneration in D. japonica, we investigated the morphogenesis of regenerating eyes under the stereomicroscope and the transcripts expression levels of eight genes involved in this process by quantitative real-time PCR. The eight genes were Djeya, Djsix-1, Eye53, DjotxA, Djpax6, Djopsin, Djnetrin and 1020HH. The results showed that each gene was of different expression pattern at distinct regeneration stage and these eight genes could be divided into three groups according to the expression levels at different time points and the morphogenesis during eye reconstruction: (1) the early expression group, including Djeya, Djsix-1, Eye53, and DjotxA, which expression levels were significant increase from 1 to 3days after amputation; (2) the medium-term expression group, only including one gene, Djpax6, which expression level reached the peak on day 5; and (3) the late expression genes, including Djopsin, Djnetrin and 1020HH, which gradually increase transcription with the eye regeneration. Our data suggested that eye reconstruction was the results of polygenic services and the genes in the same group might have similar role or function in symphony.