Dresden 2009 – scientific programme
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BP: Fachverband Biologische Physik
BP 18: Regulation and Signaling
BP 18.6: Talk
Thursday, March 26, 2009, 11:30–11:45, HÜL 186
Transfection on the Single Cell Level: Interplay of Stochastic Delivery and Deterministic Expression — •Jan-Timm Kuhr1,2,3, Gerlinde Schwake3, Simon Youssef1,3, Joachim O. Rädler1,3, and Erwin Frey1,2,3 — 1Center for NanoScience (CeNS) — 2Arnold Sommerfeld Center for Theoretical Physics — 3Fakultät für Physik, Ludwig-Maximilians-Universität, Muinch, Germany
Non-viral delivery of exogenous genes to cells, known as transfection, is a key technology in gene therapy. To analyze transfection on the single cell level we used complexes of cationic lipids/polymers and fluorophore-encoding plasmids. Statistical analysis of abundant expression curves permits conclusions on key properties of complex delivery.
Expression onset time distributions depict strong cell phase dependence of successful transfection.
Distributions in maximal expression are analyzed within a theoretical model, which describes plasmid delivery as a multi-step stochastic process followed by deterministic gene expression. The model suggests that noise in transfection is primarily caused by small number fluctuations intrinsic to gene delivery. We infer the steady state ratio of proteins per plasmid, the number of activated plasmids per complex, and the average number of delivered complexes from single cell data. Simultaneous transfection with plasmids coding for distinct proteins yields consistent percentages of non-fluorescent, mono- and, dichromatic cells, substantiating our semi-stochastic model of transfection and the resulting distribution of active plasmids per cell.