Use of Transposable Reporters in the Analysis of Bacterial Regulatory Networks

Transposable elements are genetic entities that have the capacity to promote their own translocation from one site to another within a genome. Initially discovered in Zea mays by Barbara McClintock at the Cold Spring Harbor Laboratory, transposable elements have been found to populate the genomes of all forms of life. In bacteria, the discovery of transposons significantly enhanced genetic analyses; they have been widely used to make insertion mutants and have inspired elegant strategies for strain construction and in vivo genome engineering. In one application, transposons have been modified to include a reporter gene engineered in such a way that the reporter can become fused to a chromosomal gene upon inserting randomly in the bacterial chromosome. Screening this type of transposon library for expression of the reporter under different conditions allows identifying fusions that respond coordinately to a specific treatment or stress condition. Characterization of these fusions provides a genome-wide snapshot of the organization of a bacterial regulatory network.