Cooperation between giant DNA molecules and actin filaments in a microsphere

We report the appearance of a spatially segregated state in a microsphere as a result of cooperation between actin filaments and giant DNA molecules. When the coexisting actin concentration is high enough, DNA molecules are excluded toward the surface by forming an assembly with actin filaments. With a decrease in the actin concentration, actin filaments tend to dissolve within the sphere whereas DNA molecules remain to be excluded onto the surface. When the actin concentration becomes still lower, DNA molecules dissolve within the sphere by avoiding surface attachment. We interpret these experimental trends by introducing the concept of an "exclusion zone" for actin filaments within a microsphere.