Dissection of C. elegans behavioral genetics in 3-D environments.

Namseop Kwon,Young-Jai You,Ara B Hwang,Seung-Jae V Lee,Jung Ho Je

doi:10.1038/srep09564

Abstract

The nematode Caenorhabditis elegans is a widely used model for genetic dissection of animal behaviors. Despite extensive technical advances in imaging methods, it remains challenging to visualize and quantify C. elegans behaviors in three-dimensional (3-D) natural environments. Here we developed an innovative 3-D imaging method that enables quantification of C. elegans behavior in 3-D environments. Furthermore, for the first time, we characterized 3-D-specific behavioral phenotypes of mutant worms that have defects in head movement or mechanosensation. This approach allowed us to reveal previously unknown functions of genes in behavioral regulation. We expect that our 3-D imaging method will facilitate new investigations into genetic basis of animal behaviors in natural 3-D environments.

Highlights

The nematode Caenorhabditis elegans is a widely used model for genetic dissection of animal behaviors
We proposed 3-D Worm Tracker (3DWT) 2.0 for behavioral analysis of C. elegans in 3-D environments
A red arrowhead indicates the focal point. (b) Automatic 3-D tracking process of a single worm. (c) Reconstruction of a 3-D posture of a worm based on back-projections of x, y- and z-views. (d) A trace and three representative reconstructed images of a worm moving in a gelatin cube (>2 cm3) for 3 minutes

Summary

Introduction

The nematode Caenorhabditis elegans is a widely used model for genetic dissection of animal behaviors. We developed an innovative 3-D imaging method that enables quantification of C. elegans behavior in 3-D environments. For the first time, we characterized 3-D-specific behavioral phenotypes of mutant worms that have defects in head movement or mechanosensation. This approach allowed us to reveal previously unknown functions of genes in behavioral regulation. X-ray microtomography[5] or laser diffraction analysis[6], reported for quantification of the worm movement in 3-D environments, is not appropriate for behavioral study of the worm. A dual-view imaging method, known as 3-D Worm Tracker (3DWT), recently developed for quantification of C. elegans movement in 3-D environments[7], had two major limitations. The 3DWT 2.0 has a potential for applications to analysis of various worm behaviors to elucidate genetic basis of natural animal behaviors

Methods

Results

Conclusion