DNA-Mediated Fusion Between Small Vesicles and a Planar, Tethered Bilayer Patch

Abstract

We have previously shown that DNA-lipid conjugates can be used to mediate membrane fusion between small vesicles and also to construct membrane architectures, such as a DNA-tethered lipid bilayer patch which is distanced from a glass coverslip by 8 nm long DNA duplex tethers. We currently employ these bilayer patches in a model vesicle fusion system, studying the fusion (both lipid-mixing and content-mixing) of small vesicles to the bilayer patches, where fusion is mediated by complementary DNA-lipid partners in a geometry similar to that of SNARE-mediated membrane fusion. This model system allows us to quantitatively describe important aspects of membrane fusion, such as the dependence of fusion on DNA-lipid concentration, the numbers of DNA-duplexes involved in the fusion process, the role of proximity and membrane curvature on the fusion reaction. We have also developed a kinetic model describing the distribution of docking-to-fusion wait times and find that these wait times are exponentially distributed, implying a stochastic process which initiates fusion. Insights into the biological membrane fusion process are discussed.View Large Image | View Hi-Res Image | Download PowerPoint Slide