Role of microRNA miR124c during planarian brain regeneration.. Schmidtea mediterranea strain:Sexual

The unique capacity of planarians to regenerate their central nervous system provides an opportunity to investigate neural differentiation, neural patterning, organization and scaling of brain and photoreceptor. Multiple studies have identified microRNAs as key regulators of diverse cellular processes in metazoans. Among the several miRNAs discovered, the miR-124 family of microRNAs are highly conserved and are known to regulate neurogenesis by facilitating neural differentiation. Here, we studied the role of miR-124c in planarian brain regeneration and neural patterning. We have shown that miR-124c is expressed day 3 post-amputation in the anterior regenerating tissue of planarians. It regulates key pathways such as axon guidance and planar cell polarity essential for accurate neural patterning and neural growth during anterior regeneration. We also showed that miR-124c regulate slit-1, an axon guidance protein expressed in the midline, by controlling the Notch pathway. Together, our results reveal a novel role for miR-124c in regulating axon guidance cues and the planar cell polarity pathway. This is essential for precise neural growth and neural wiring, which is necessary for the regeneration of both functional brain and photoreceptors.