Viraat Goel (HANSEN LAB)

Mapping 3D Genome Architecture at Nucleosome Resolution with Tiled Micro-C

Chromosome conformation capture (3C) techniques have uncovered 3D genomic structures spanning the kb and Mb scales over the past two decades. However, traditional techniques are ill-equipped to map genomic microarchitecture at nucleosome resolution, which is necessary to connect 3D genomic structures to their functions. Here, we introduce Tiled Micro-C, a new 3C technique which overcomes these limitations by mapping the 3D genome at unprecedented detail to unravel the functions of the 3D genome.

Harvey Yang (HANSEN LAB)

DNA Double-strand Break End Synapsis by DNA Loop Extrusion

Non-homologous end joining (NHEJ) is the primary pathway for DSB repair, during which the two DSB ends must be first brought back into proximity (synapsis). While synapsis is generally assumed to occur through passive diffusion, we show that passive diffusion is unlikely to achieve the NHEJ efficiency observed in vivo. By combining experimentally constrained simulations and theory, we demonstrate a loop extrusion model achieving fast synapsis with near 100% efficiency. We propose that loop extrusion plays an underappreciated role in DSB repair.