Smed-dynA-1 is a planarian nervous system specific dynamin 1 homolog required for normal locomotion

Abstract

Dynamins are GTPases that are required for separation of vesicles from the plasma membrane and thus are key regulators of endocytosis in eukaryotic cells. This role for dynamin proteins is especially crucial for the proper function of neurons, where they ensure that synaptic vesicles and their neurotransmitter cargo are recycled in the presynaptic cell. Here we have characterized the dynamin protein family in the freshwater planarian Schmidtea mediterranea and showed that it possesses six dynamins with tissue specific expression profiles. Of these six planarian homologs, two are necessary for normal tissue homeostasis, and the loss of another, Smed-dynA-1, leads to an abnormal behavioral phenotype, which we have quantified using automated center of mass tracking. Smed-dynA-1 is primarily expressed in the planarian nervous system and is a functional homolog of the mammalian Dynamin I. The distinct expression profiles of the six dynamin genes makes planarians an interesting new system to reveal novel dynamin functions, which may be determined by their differential tissue localization. The observed complexity of neurotransmitter regulation combined with the tools of quantitative behavioral assays as a functional readout for neuronal activity, renders planarians an ideal system for studying how the nervous system controls behavior.

Nervous system development and regeneration in freshwater planarians

“…21 This suggests that the photoreceptor neurons or the transduction of their signals in the brain is not functioning correctly. Inhibition of genes involved in synaptic transmission 79,152,155 or neuropeptide processing also have profound effects on nervous system function. 51,156 Knockdown of Smed-pc2 impairs mobility 51,156 and disruption of dopaminergic signaling leads to severe locomotion defects.…”

Adult and regenerating planarians respond differentially to chronic drug exposure

“…Decreases in motility have been found in adult flatworms acutely exposed to MDL-12,330A (Matsuyama et al 2004), mianserin (Currie and Pearson 2013;Talbot et al 2014;Chan et al 2016;Shettigar et al 2021), sertraline (Thumé and Frizzo 2017;Weeks et al 2018), and high concentrations of caffeine (Best and Morita 1982;Moustakas et al 2015). Previous studies on the effects of caffeine in planarians have only found behavioral effects at much higher concentrations than we tested here (mM instead of µM).…”

Adult and regenerating planarians respond differentially to chronic drug exposure

“…Acute exposure to mianserin has previously been shown to induce muscle-based movement in Schmidtea mediterranea planarians (Currie and Pearson 2013; Talbot et al 2014). Our finding that low to mid-concentrations of mianserin cause a significant induction of muscle waves suggests that mianserin acts similarly in D. japonica .…”