Topology-dependent anomalous dynamics of ring and linear DNA are sensitive to cytoskeleton crosslinking

TL;DR

This study investigates how the cytoskeleton influences the movement and shape of ring and linear DNA molecules, revealing that crosslinking affects their diffusion differently due to their topology.

Contribution

It uncovers the topology-dependent effects of cytoskeleton crosslinking on DNA dynamics using combined single-molecule tracking and microscopy techniques.

Findings

Ring DNA exhibits heterogeneous subdiffusion hindered by crosslinking.

Linear DNA shows facilitated subdiffusion with crosslinking.

Cytoskeleton threading significantly impacts ring DNA mobility.

Abstract

Cytoskeletal crowding plays a key role in the diffusion of DNA molecules through the cell, acting as a barrier to effective intracellular transport and conformational stability required for such processes as transfection, viral infection, and gene therapy. Here we elucidate the transport properties and conformational dynamics of linear and ring DNA molecules diffusing through entangled and crosslinked composite networks of actin and microtubules. We couple single-molecule conformational tracking with differential dynamic microscopy to reveal that ring and linear DNA exhibit surprisingly distinct transport properties that are influenced differently by cytoskeleton crosslinking. Ring DNA coils are swollen and undergo heterogeneous and biphasic subdiffusion that is hindered by crosslinking. Conversely, crosslinking actually facilitates the single-mode subdiffusion that compacted linear chains exhibit. Our collective results demonstrate that transient threading by cytoskeleton filaments plays a key role in the dynamics of ring DNA, whereas the mobility of the cytoskeleton dictates transport of linear DNA.