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

Jared A Talbot,Ko W Currie,Eva-Maria S Collins,Bret J Pearson

doi:10.1242/bio.20147583

Abstract

ABSTRACTDynamins 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.

Highlights

Planarians are one of a few organisms that have the capability of regenerating an adult nervous system de novo upon injury
We found that 3 planarian dynamins clustered strongly with a group that includes fly Shibire and C. elegans Dyn-1, as well as Dynamins I–III in vertebrates (Fig. 1)
The planarian S. mediterranea has six dynamins, which display tissue specific expression profiles; two of these are essential for tissue homeostasis and one for normal locomotion

Summary

Introduction

Planarians are one of a few organisms that have the capability of regenerating an adult nervous system de novo upon injury. Mammals have three dynamin genes with distinctive expression patterns (Cook et al, 1996; Clark et al, 1997; Ferguson et al, 2007): Dynamin I is expressed primarily in the brain, Dynamin II is ubiquitous, and Dynamin III is expressed in the testis, lungs and brain. Each of these dynamins exists in at least four isoforms, which are generated by alternative splicing of mRNA (Urrutia et al, 1997)

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