One important tool in molecular biology takes advantage of promoter fusions where the expression of one gene is controlled by the promoter or regulatory elements of another gene. Promoter fusions engineered in vitro can help to determine how gene expression is regulated in cells and whole organisms. Promoter fusions generated in vivo, for example, by promoter trapping, can help to identify new genes and generate useful genetic resources for dissecting important biological processes. A binary effector–reporter system can be used to direct the production of a protein of interest in specific cells of an organism for functional studies. It can also be used to direct the production of interference ribonucleic acid molecules that can inhibit the activity of their target genes in specific cells of an organism. The GAL4–UAS version of this binary system is a valuable genetic tool for investigations of mechanisms that control development.
Key Concepts:
The first step towards expressing a gene is transcription.
Gene transcription is controlled by regulatory DNA sequences (elements) that contain binding sites for regulatory proteins.
The regulatory DNA element of one gene can exert its effect on the expression of another gene in a chimaeric (fusion) construct.
Engineered fusion constructs can be introduced to cells or whole organisms.
Reporter genes are used in fusion constructs because their encoded proteins can be monitored or assayed easily.
Reporter fusion constructs can be used to analyse the functions of the regulatory DNA elements.
An effector–reporter system can be used to study the relationship between a regulatory DNA element and the regulatory proteins that bind to it.
Promoter trapping and enhancer trapping are useful techniques to generate genome‐scale resources for genetic studies.
A binary effector–reporter system (a version of which is commonly known as the GAL4–UAS system) is a powerful genetic tool.
Keywords: promoter; enhancer; transcription; gene fusions; activators