Bundle Formation in a Crowded Environment with Giant DNA and F-Actin inside a Micro-Meter Scale Closed-Space

It is known that actin play the essential role in the regulation of the structure and function in cellular and cell nuclei systems. DNA and actin filaments are the two major components of cell nuclei. We developed an artificial cell nuclei model with T4 DNA and F-actin in phospholipid-coated micro-meter scale closed spheres (MPDs). In a MPD, the mixture of T4 DNA and F-actin was found to phase-separate into F-actin phase (P 1 ) and T4 DNA rich phase (P 2 ), where the manner of the segregation is dependent on the total volume fraction of F-actin and T4 DNA. In addition, we found that, in a MPD, T4 DNA forms bundles in a crowded micro-space with F-actin even in the absence of multivalent cations.