Biology subjects

Sutani, T.

Publications and source records attributed to Sutani, T..

3 recordsLinked to original sources

bioRxiv2025

Cohesin acts as a transcriptional gatekeeper by restraining pause-release to promote processive elongation

Cohesin organizes 3D chromatin architecture, including promoter-enhancer loops, yet its loss has surprisingly modest effects on steady-state gene expression. We address this paradox by demonstrating that cohesin acts at different stages of transcription. First, it promotes Pol II promoter recruitment by facilitating enhancer-promoter communication that maintains active promoter chromatin states. Second, it delays pause release by transiently associating with the transcriptional machinery during the pause-release transition. Kinetic modelling suggests that reduced Pol II recruitment and enhanced pause release have compensatory effects, contributing to minimal changes in steady-state gene expression across genes upon cohesin loss. In contrast, cohesin depletion impairs robust transcriptional induction in response to external stimuli. Moreover, cohesin ensures sufficient pausing duration as a quality-control-like step to promote elongation complex assembly and transcription processivity. Here, we show that cohesin regulates multiple steps of transcription, offering mechanistic insight into cohesin-related diseases, including cancers and cohesinopathies.

molecular biology↗

bioRxiv2024

Controlling mechanism of the Scc2-cohesin interaction to restrict peri-centromeric DNA loop expansion and facilitate mitotic chromosome segregation

Cohesin exhibits DNA loop extrusion activity when bound to an ATPase activator Scc2 (NIPBL in humans), thereby organizing higher-order chromosome folding. In budding yeast, the majority of the chromosome-bound cohesins lack association with Scc2. It remains unknown how the interaction between Scc2 and cohesin is regulated on the chromosome and what physiological consequences malfunction in this regulatory mechanism causes. Here, we show that simultaneous deletion of Wpl1 and Eco1, two of the known cohesin regulators, resulted in Scc2 co-localization with cohesin around the centromeres of metaphase chromosomes. In these cells, the pericentromeric DNA loops were enlarged to connect the centromere to the cohesin/Scc2 co-bound sites at distances of up to a few hundred kb, indicating highly active loop extrusion by the Scc2-associated cohesin. Furthermore, we demonstrated that {Delta}wpl1 {Delta}eco1 cells exhibited a delay in the progression of mitotic chromosome segregation, a phenotype dependent on the presence of Scc2 in metaphase. These findings suggest that Wpl1 and Eco1 cooperatively regulate Scc2-cohesin interaction on chromosomes, restrict the size of the pericentromeric DNA loops, and facilitate mitotic chromosome segregation.

molecular biology↗

bioRxiv2023

Loop-extruding Smc5/6 organizes transcription-induced positive DNA supercoils

The Structural Maintenance of Chromosome (SMC) protein complexes cohesin, condensin and the Smc5/6 complex (Smc5/6) are essential for chromosome function. At the molecular level, these complexes fold DNA by loop extrusion. Accordingly, cohesin creates chromosome loops in interphase, and condensin compacts mitotic chromosomes. However, the role of Smc5/6s recently discovered DNA loop extrusion activity is unknown. Here, we uncover that Smc5/6 associates with transcription-induced positively supercoiled chromosomal DNA at cohesin-dependent chromosome loop boundaries. Mechanistically, single-molecule imaging reveals that dimers of Smc5/6 specifically recognize the tip of positively supercoiled DNA plectonemes, and efficiently initiates loop extrusion to gather the supercoiled DNA into a large plectonemic loop. Finally, Hi-C analysis shows that Smc5/6 links chromosomal regions containing transcription-induced positive supercoiling in cis. Altogether, our findings indicate that Smc5/6 controls the three-dimensional organization of chromosomes by recognizing and initiating loop extrusion on positively supercoiled DNA.

molecular biology↗