12.45.13.00 Eleni Chrysostomou
We have started to unravel the neurogenesis transcriptional network in Hydractinia by generating transgenic reporter animals expressing fluorescent proteins under the control of neurogenesis-related genes, and a Piwi1 reporter line that marks stem cells. By generating these lines, we were able to trace neuronal cells and their precursors to study their fate in regeneration. Tracing of individual differentiated neurons showed that the injured nervous system is re-established by de novo neurogenesis rather than by migration/proliferation of existing neurons. Using Piwi1, SoxB2 and Rfamide reporter lines, we were able to sort cells along the neurogenesis pathway for subsequent RNA sequencing. In addition, these lines where further analyzed using Imaging Flow Cytometry by focusing on the level of the transgene expression and morphology of the cells. Working with our animal model is a novel opportunity to shed light on neural lineage specification markers as well as understanding how commitment of cells to a certain lineage is established.
In addition, the role of the SoxB genes during embryonic development it seems to be more diverse than originally thought. SoxB1 knockdown affects many lineages as it is expressed in stem cells, whereas SoxB2 knockdown affects specifically the neuronal lineage as it is expressed in neural progenitor cells with a preference to distinct neuronal subtypes. Along with over-expression studies, SoxB1 seems to act in a similar manner with the mammalian Sox2 as it is required for cells to remain in a pluripotent state. These data provide an insight into a potentially conserved role of SoxB genes between bilaterians and cnidarians.