Elucidating the Membrane Dynamics and Encapsulation Mechanism of Large DNA Molecules Under Molecular Crowding...

The conservation throughout evolution of membrane-bound structures that encapsulate genomic material indicates the existence of a simple, physical mechanism that facilitates the enclosing of long-stranded DNA by lipid bilayers. This study aimed to elucidate such a mechanism by investigating how molecular crowding promotes the spontaneous enveloping of model DNA into lipid bilayer membranes. Using fluorescence microscopy and giant unilamellar vesicles (GUVs) we showed that a 166 kb DNA molecule coencapsulated with a model crowder attaches to the inner membrane of the GUVs as they osmotically deflate and after the DNA-membrane complex buds out. The set of results is consistent with the hypothesis that the depletion volume effect is responsible for the spontaneous encapsulation of DNA in the GUVs. This phenomenon may offer novel insights into the basic mechanisms governing membrane encapsulation of long-stranded nucleic acids found in celluar sytems that are independent of genetic control.