Dynamic
control of cell–cell adhesion. (A) Sketch showing
the reversibility of the cell–cell linkage by using toehold-mediated
strand-displacement. A431D cells are linked with a DNA strand which
contains a free overhang (toehold) functionalized with Atto647N (i).
Upon addition of an invader strand in excess (ii), the linker strand
is displaced and the link between the cells is broken (iii). (B) Representative
confocal images of cells expressing SNAP-E-cadherin-mCherry (cyan)
incubated with the DNA linker-Atto647N (red) before and after the
addition of the invader strand. Scale bar, 50 μm. Quantification
of the fluorescence intensity normalized to the maximum value over
time of SNAP-E-cadherin-mCherry and DNA linker-Atto647N. The invader
strand is added at t = 1.8 min, indicated by the
dotted line. Mean values are plotted and error bars indicate the standard
deviation. Plots generated from N = 3 independent
experiments and n = 31 measurements. (C) Live-cell
time-lapse snapshots of A431D cells expressing SNAP-E-cadherin-mCherry
imaged by interference reflection microscopy without addition of the
DNA linker. Images representative of N = 2 independent
experiments. Scale bar, 10 μm. (D) Live-cell time-lapse snapshots
showing the formation of a cell–cell junction between A431D
cells expressing SNAP-E-cadherin-mCherry after the addition of the
DNA linker: top row, interference reflection microscopy; middle row,
SNAP E-cadherin (blue); bottom row, actin cytoskeleton labeled with
SiR actin (red). Images are representative of N =
2 independent experiments. Scale bar, 10 μm.