Forward Genetic Screen Using Zebrafish to Identify New Genes Involved in Myelination

: Zebrafish are now well established as the preeminent vertebrate model with which to carry out gene discovery/forward genetic screens to identify the molecular genetic basis of biological processes. Gene discovery screens in zebrafish have already provided novel insight into mechanisms of glial cell development and function. The vast majority of genetic screens in zebrafish are based around a three generation screen that starts with the random induction of mutations in adult males using the chemical mutagen ENU. Here we outline the methods that underlie this type of screen, detailing each step, from ENU mutagenesis, through the breeding schemes required to recover homozygous mutant animals in subsequent generations, the screening procedure itself, with a focus on the analysis of myelinating glia, and the subsequent confirmation of mutant phenotypes.