Insights on the Control of Yeast Single-Cell Growth Variability by Members of the Trehalose Phosphate Synthase (TPS) Complex.

Single-cell variability of growth is a biological phenomenon that has attracted growing interest in recent years. Important progress has been made in the knowledge of the origin of cell-to-cell heterogeneity of growth, especially in microbial cells. To better understand the origins of such heterogeneity at the single-cell level, we developed a new methodological pipeline that coupled cytometry-based cell sorting with automatized microscopy and image analysis to score the growth rate of thousands of single cells.

A Promoter Variant Confers Constitutive Noisy Bimodal Expression That Increases Oxidative Stress Resistance in Yeast.

Higher noise in the expression of stress-related genes was previously shown to confer better resistance in selective conditions. Thus, evolving the promoter of such genes toward higher transcriptional noise appears to be an attractive strategy to engineer microbial strains with enhanced stress resistance. Here we generated hundreds of promoter variants of the gene involved in oxidative stress resistance in and created a yeast library by replacing the native promoter by these variants at the native locus.

Bimodality of gene expression from yeast promoter can be instigated by DNA context, inducing conditions and strain background.

Bimodality in gene expression is thought to provide a high phenotypic heterogeneity that can be favourable for adaptation or unfavourable notably in industrial processes that require stable and homogeneous properties. Whether this property is produced or suppressed in different conditions has been understudied. Here we identified tens of Saccharomyces cerevisiae genomic fragments conferring bimodal yEGFP expression on centromeric plasmid and studied some of these promoters in different DNA contexts, inducing conditions or strain backgrounds.