Figure 1. ERK-KTR biosensor in Macrostomum lignano red arrow points at the cytoplasm and yellow at the nucleus.
Flatworms have remarkable regeneration capabilities. They are able to regrow their whole body after amputation, including their reproductive organs. They can do this thanks to a population of adult stem cells, collectively called neoblasts. One of the fascinating aspects of flatworm regeneration is the positional control of the process along the anterior-posterior axis (head-tail). How cells know where specific body parts need to be reconstructed is a question that still lacks a full answer. Our current state of knowledge is that Wnt pathway and the mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK) signaling play major role in this process. However, most of the research done on flatworms is based on information inferred from experiments on gene knock-down via RNA interference (RNAi). Gene activation and overexpression studies are absent in planarians, the more common flatworm model organisms, because of the lack of transgenic methods available for these animals. I am trying to use the ERK-KTR biosensor in Macrostomum lignano (Fig. 1), to track ERK signaling and test the function of genes shown to be involved in positional control during growth and regeneration. I am also adapting the infrared laser evoked gene operator (IR-LEGO) technology to use with the previously established HSP20 promoter (Fig. 2). This will enable me to track the cell fate in vivo and overexpress selected genes even on a single cell level.
The research is financed by the Mistubishi Foundation grant.
Figure 2. Expression of mScarlet under the HSP20 promoter 24 hours after induction using IR-LEGO. The lightning bolts point at the targeted sites.