# Structural Diversity of Mitochondria in the Neuromuscular System across Development Revealed by 3D Electron Microscopy

## TL;DR

This study uses 3D electron microscopy to show how mitochondria structures in the neuromuscular system change during development and how these changes support neural function.

## Contribution

The study introduces semi-automated methods for reconstructing mitochondria in C. elegans and reveals preserved structural properties across development.

## Key findings

- Mitochondria structural properties in neurons correlate with synaptic connections and are preserved across development.
- DRP-1 mutants with impaired mitochondrial fission show behavioral deficits, highlighting the importance of mitochondria structure.
- Dauer neurons and muscles exhibit distinct mitochondrial features, possibly as an adaptive mechanism for specific developmental needs.

## Abstract

As an animal matures, its neural circuit undergoes alterations, yet the developmental changes in intracellular organelles to facilitate these changes is less understood. Using 3D electron microscopy and deep learning, the study develops semi‐automated methods for reconstructing mitochondria in C. elegans and collected mitochondria reconstructions from normal reproductive stages and dauer, enabling comparative study on mitochondria structure within the neuromuscular system. It is found that various mitochondria structural properties in neurons correlate with synaptic connections and these properties are preserved across development in different neural circuits. To test the necessity of these universal mitochondria properties, the study examines the behavior in drp‐1 mutants with impaired mitochondria fission and discovers that it causes behavioral deficits. Moreover, it is observed that dauer neurons display distinctive mitochondrial features, and mitochondria in dauer muscles exhibit unique reticulum‐like structure. It is proposed that these specialized mitochondria structures may serve as an adaptive mechanism to support stage‐specific behavioral and physiological needs.

Mitochondria across the entire neuromuscular system have been comprehensively reconstructed at different developmental stages using 3D electron microscopy. Fundamental structural principles related to synaptic function are preserved across development, and these morphologies are adapted to ensure effective neural circuit function. Notably, the alternative stage, dauer, exhibits distinct structural properties in both neurons and muscles.