Methods to study nervous system laterality in the Caenorhabditis elegans model system

Abstract

The anatomically and genetically very accessible nervous system of the nematode Caenorhabditis elegans, composed of a total of 302 neurons in the hermaphrodite, displays a number of striking neuronal lateralities which come largely in two forms: unilateral neurons found only on one side of the nervous system and functional differences in otherwise bilaterally symmetric neuron pairs. Two recent reviews have described in detail the genetic mechanisms that specify the most prominent sensory lateralities in two bilaterally symmetric sensory neuron classes in C. elegans. In this Neuromethods chapter, we provide a general overview of the specific methods and opportunities that exist in C. elegans to identify lateralities, to decipher their functional relevance and to dissect the genetic control mechanisms that establish these lateralities. These specific advantages include (a) the ability to identify and visualize neuronal lateralities on the anatomical, gene expression, and neuronal activity level with single cell resolution; (b) the ability to assign function to lateralized neurons using behavioral analysis and genetic manipulation of neuronal activity; (c) the ability to conduct genetic screens for mutants that disrupt lateralities, thereby deciphering the genetic patterning mechanisms that instruct neuronal lateralities.