Zebrafish for the Study of Enhancer Activity in Human Traits and Disease

Abstract

Enhancers are genetically encoded elements that are critical for controlling gene expression. Despite the importance of enhancers in development, normal biological function, and disease, they have been historically overlooked and remain understudied. To understand how enhancers function, appropriate molecular tools are required that can capture the temporal and spatial function of enhancers within appropriate biological contexts. Zebrafish are an excellent in vivo model for the study of enhancer elements and the genetic variants that alter their function. Because zebrafish larvae are transparent, transgenes encoding enhancers tagged by fluorescent reporters can be visualized in the tissues and developmental stages where the enhancers function. Transgenesis of enhancers can be achieved using various plasmid technologies and transgene integration methods. Here, we describe the history and most recent developments in the zebrafish enhancer assay, from vector designs to various transgene integration techniques. We go on to describe how the application of these assays have been integral for our understanding of genetic variants found in humans and within enhancers that can contribute to both human Mendelian and complex polygenic disease.