Cloning and characterization of DjPRPS gene in freshwater planarian Dugesia japonica

Objective: To clone the phosphoribosyl pyrophosphate synthetase gene from Dugesia japonica, and to do the bioinformatics and spatial expression analysis of the gene. Methods: The phosphoribosyl pyrophosphate synthetase gene (DjPRPS) was cloned from Dugesia japonica using the rapid amplification of cDNA ends method and its sequence was analyzed with biological softwares. Spatial expression pattern of the gene was detected by whole-mount in situ hybridization. Results: The full length cDNA of DjPRPS was 1,086 bp, containing a 80 bp of 5'-untranslated region, a 55 bp of 3'-untranslated region and a 951 bp of open reading frame encoding a protein of 316 amino acids with a calculated molecular mass of 35.18 kDa and isoelectric point of 8.14. The deduced amino acid sequence shared the conserved eukaryotic PRPS family motif. Phylogenetic analysis supported the traditional concept of zoological taxonomy in large scale. Intense positive signals were detected as bilateral lines of patches in the ventral side where the ovaries and yolk glands located in the intact sexual planarians. In the regenerating planarians, the expression pattern was similar to that of the intact samples, and no intense transcipt signals were detected in the blastema. Conclusion: DjPRPS sequence was highly homologous with that of other eukaryotic phosphoribosyl pyrophosphate synthetase gene. Intense transcript signals of DjPRPS were not detected in the blastema but in ovaries and yolk glands, suggesting that its function was probably reproduction-related and maybe not involved in regeneration.