A pumilio homolog in Polycelis sp.

Pumilio proteins (PUMs), members of the pumilio/fem-3 mRNA-binding factor (PUF) family, are eukaryote-specific RNA-binding proteins. We isolated a 2,048-basepair cDNA fragment of a pumilio homolog from the planarian flatworm Polycelis sp. This pumilio protein (PyPUM) contains a conserved pumilio homology domain (PUM-HD) consisting of eight repeats and two flanking half repeats. PyPUM shows high similarity to Dugesia japonica pumilio (DjPUM) from another planarian D. japonica, and their PUM-HD also shows high similarity to each other. Furthermore, our data showed that there is a flatworm-specific spacer between repeats 7 and 8. Phylogenetic analysis showed that PyPUM has a closer relationship to other PUM homologs from flatworms. These results provide a foundation for future functional studies of pumilio gene in Polycelis sp.