Project to image the folding of DNA by cohesin funded
Scientists from the labs of Jan-Michael Peters and David Haselbach, as well as collaborators at IMBA and the University of Linz, have been awarded a WWTF grant to image DNA folding by cohesin through time resolved single molecule light, atomic force and cryo-electron microscopy.
Eukaryotic genomes are folded into loops and topologically associating domains (TADs) which contribute to chromatin structure, gene regulation and recombination. These long-range interactions depend on cohesin, an ATPase complex first identified for its role in sister chromatid cohesion.
Whereas cohesin is thought to mediate cohesion as a passive topological linker, it has been proposed that cohesin actively forms loops by an unknown extrusion mechanism. Consistent with the latter hypothesis, the lab of IMP Scientific Director Jan-Michael Peters recently found that single cohesin molecules are able to rapidly fold DNA into loops. These findings were reported only last month in the journal “Science”.
But how cohesin interacts with DNA and folds it into loops remains unknown and lies at the core of the project that now gained support by the funding agency WWTF (Vienna Science and Technology Fund).
The project aims to image DNA folding by human cohesin at the single molecule level. The multidisciplinary project team will draw from biochemistry, structural biology and biophysics in attempting to image DNA folding at multiple scales of spatial and temporal resolution, using a combination of high-speed atomic force microscopy, Förster resonance energy transfer and “time-resolved” cryo-electron microscopy. The function of cohesin movements visualised by these techniques will be tested by mutagenesis and confocal imaging in cells. This multimodal imaging approach should reveal how cohesin folds DNA, which will be key for understanding genome organisation, regulation and function.
WWTF will support the project with 700,000 Euro over the next four years. Jan-Michael Peters is the coordinator, with the IMP’s David Haselbach and Peter Hinterdorfer of the Johannes Kepler University in Linz as co-principal investigators and Anton Goloboroko as associated PI. According to WWTF, the decision to fund the project was based on the recommendation of a 7-person international jury and a written peer review process. Out of 20 submitted full proposals, the jury selected six projects for funding.