The C-Trap® provides the world’s first dynamic single-molecule microscope to allow simultaneous manipulation and visualization of single-molecule interactions in real time.
The nuclear envelope protects the genome from mechanical stress during processes such as migration, division, and compression , but how it buffers forces at the scale of DNA remains unclear. Here, we utilize optical tweezers to show that a multivalent protein–DNA co-condensate containing the nuclear envelope protein LEM2 and the DNA-binding protein BAF shield DNA beyond its melting point at 65 pN. Under load, their collective assembly induces an unconventional DNA stiffening effect that provides mechanical reinforcement, dependent on the intrinsically disordered region (IDR) of LEM2. Within cells, these components form an elastic surface hydrogel at the nuclear periphery, visible as a continuous surface by cryo-electron tomography. Disruption of this surface hydrogel increases DNA damage and micronuclei formation during nuclear deformation. Together, this work expands the functional repertoire of condensates, revealing a load-responsive nuclear surface hydrogel at the mesoscale that mitigates mechanical stress.
Precisely manipulating genetic material at the single molecule level is gaining importance across life sciences – and so do the tools that allow researchers to do exactly that. The C-Trap system combines single molecule fluorescence microscopy with optical tweezers to manipulate DNA, allowing researchers to directly observe and track molecular events as they occur. Designing and creating specific DNA constructs is crucial for maximizing the potential of single molecule studies. In this application note we introduce the powerful combination of cutting edge biochemistry and single-molecule visualization methods to increase throughput and maximize the results gained from each individual measurement.