Control over the level and timing of gene activity does not only offer advantages over more traditional genetics approaches such as gene knockouts or constitutive overexpression but is indispensable for many applications. In particular, understanding system-level properties and constructing artificial cellular behaviors frequently require the independent, temporally precise, and reversible manipulation of different nodes in a genetic network.
In Saccharomyces cerevisiae, a widely used organism in research and industry, the most common way of tuning the level of gene expression is by regulating transcription. Inducible systems are widely used in systems biology for studying the dynamics, topology, and stochasticity of genetic networks.
Many commonly used inducible transcriptional systems in budding yeast are regulated by small metabolites such as galactose, methionine, or copper. Using nutrients to control gene expression has the advantage that the relevant transcription factors are already present in cells and have been fine-tuned over the course of the evolution. On the other hand, the drawback is that changes in nutrient levels generally also affect metabolism. To avoid this, synthetic systems have been created which respond to compounds not naturally present in the host. While synthetic systems are usually orthogonal to cell physiology, they can nevertheless have an effect on cellular growth, for example, due to the toxicity of the inducer. More recently, light sensors from bacteria and plants have been adapted for use as transcriptional control systems in budding yeast. In contrast to the other systems for manipulating cellular processes, light provides a rapid, noninvasive, and convenient means of control.
For precise control of gene activity, inducible systems should ideally have fast kinetics, high dynamic range, low basal activity (leakiness), and low noise. Leakiness is a poorly characterized but crucial property since for many applications it is essential to be able to turn expression truly ‘off’. Leakiness is particularly important when controlling genes that are toxic or cause changes to the genome. However, for inducible systems, most of these properties have either not been assessed precisely, not in a manner that would allow their direct comparison, or have not been determined at all. The aim of this website is to enable easy exploration of data from the publication “Multidimensional single-cell benchmarking of inducible promoters for precise dynamic control in budding yeast” with the purpose of guiding future experimental designs.