Figure 1. Microfluidic channels can control the shape of fission yeast cells.
A. Microfluidic channels to constrain the shape of fission yeast cells. Shown is a typical cell chamber made by bonding a polydimethylsiloxane (PDMS) replica (p) onto a glass-bottom dish (g). The PDMS replica contains either curved or straight microfluidic channels (c) connected to inlet (i) and outlet (o) tubings for liquid exchange.
B. A curved microfluidic channel containing fission yeast cells. Cells growing outside the channel are free to take on their natural shape, while cells growing inside the channel conform to the shape of the channel.
C. Timelapse image of a wildtype cell expressing GFP-atb2p (tubulin) (PT.72) inside a curved channel. While growing inside the channel, the cell can progress normally through the cell cycle, forming a mitotic spindle (yellow arrow) during mitosis. Time, hr:min.
D. Wildtype cells expressing mCherry-atb2p (tubulin) and the conserved microtubule bundler ase1p-GFP (PT.802). Microtubule bundles inside the bent cell reflect global changes in their location, not changes in the number and inherent antiparallel organization of individual microtubule bundles by ase1p (n=8; control cells n=14). Bar, 10 μm.
E. Plot of cell arc Radius vs. cell Length. We calculate the arc radius as: (see Appendix). We defined three regions of interest: red zone – cells are short (<14 μm), and therefore their arc radii are large (>8 μm), and no reorganization of microtubules is apparent; yellow zone – cells are between 14.4 ± 1.7 μm to 17.7 ± 0.4 μm (n=16) with arc radii between 7.4 ± 0.1 μm to 7.7 ± 0.3 μm (n=16), and unambiguous microtubule reorganization to the convex side of the cell occurs; green zone – cells >18 μm with average arc radii of 7.5 μm (n=10), and frequent and sustained contacts of microtubule tips with ectopic virgin cell cortex occurs. Cells in the green zone are capable of forming ectopic cell tips – 70% of cells in this zone showed unambiguous ectopic tip protrusion.