Role of FUSE binding protein in planarian stem cell maintenance

Abstract

The extraordinary ability of the planarians to regenerate lost body parts is dependent on the population of adult stem cells called neoblasts. RNA binding proteins are essential for neoblast maintenance and differentiation. The study here shows that FUSE binding protein (FBP), a RNA binding protein with KH domains is required for planarian regeneration and homeostasis. dsRNA mediated RNAi was employed to deplete Smed-fbp in the planarian Schmidtea meditarranea. Upon Smed-fbp RNAi there was initial blastema formation which did not develop and regressed during the course of regeneration. In homeostatic worms Smed-fbp RNAi resulted in animal curling and lesion formation on the dorsal surface. Neoblast proliferation was reduced upon Smed-fbp knockdown. The number of cells in G2/M phase was reduced, but the transcript level for Smed-pcna was upregulated. So here we hypothesize that Smed-fbp is essential for neoblast to exist G1 or S phase and make a transition to G2/M phase of the cell cycle.