DNA supercoiling

Figure 1. DNA supercoil generated by DNA twisting

Figure 1. DNA supercoil generated by DNA twisting

Figure 2. Movie showing proteins (red) binding on supercoiled DNA (green). Scale bar = 1µm

Figure 2. Movie showing proteins (red) binding on supercoiled DNA (green). Scale bar = 1µm

DNA in cells constantly undergoes topological stresses that are generated by genomic processes, such as transcription and replication. As a result, DNA takes a super-helical structure that is over- or under-wound, called DNA supercoils (Fig.1). While bacterial genomes are maintained in a globally negatively supercoiled (under-wound) state, DNA supercoiling in eukaryotes is enriched locally and correlated with transcriptionally active regions. Despite its potential importance in chromatin packaging and genome function, DNA supercoils and the associated biological processes remain largely unknown. We are interested in studying the interactions of supercoiled DNA with proteins (Fig.2) which can generate, modulate, and remove DNA supercoils by using single-molecule imaging and force-spectroscopic tools.