DNA supercoiling restricts the transcriptional bursting of neighboring eukaryotic genes

DNA supercoiling has emerged as a major contributor to gene regulation in bacteria. The impact of DNA supercoiling on transcription dynamics in eukaryotes is less clear. Here, using single-molecule dual-color RNA imaging in budding yeast, we show that transcriptional bursting of the divergent and tandem GAL genes is coupled. Upon topoisomerase degradation, supercoils that buildup from transcription inhibit subsequent transcription at neighboring genes, thereby reducing their simultaneous bursting. GAL gene transcription is inhibited more by negative than by positive supercoiling accumulation. Unlike bacteria, wildtype yeast has sufficient topoisomerase levels to minimize inhibition from supercoils at adjacent genes. Overall, we discover fundamental differences in supercoiling-mediated gene regulation between bacteria and yeast and show that rapid supercoiling release in eukaryotes ensures proper gene expression of neighboring genes. One sentence summaryTranscription causes twisting of the DNA double helix, which can inhibit transcription of adjacent genes.